diff --git a/app/src/main/AndroidManifest.xml b/app/src/main/AndroidManifest.xml
index dff6697..a48e3f5 100644
--- a/app/src/main/AndroidManifest.xml
+++ b/app/src/main/AndroidManifest.xml
@@ -2,12 +2,10 @@
 <manifest xmlns:android="http://schemas.android.com/apk/res/android"
     package="org.communiquons.android.comunic.client">
 
-    <!-- Internet access is required to access the API -->
+    <!-- Internet access is required to access the API and download medias -->
     <uses-permission android:name="android.permission.INTERNET" />
     <uses-permission android:name="android.permission.ACCESS_NETWORK_STATE" />
 
-
-
     <application
         android:allowBackup="true"
         android:fullBackupContent="@xml/backup_scheme"
@@ -16,6 +14,8 @@
         android:roundIcon="@mipmap/ic_launcher_round"
         android:supportsRtl="true"
         android:theme="@style/AppTheme">
+
+        <!-- Main activity of the application -->
         <activity android:name=".MainActivity">
             <intent-filter>
                 <action android:name="android.intent.action.MAIN" />
@@ -23,8 +23,17 @@
                 <category android:name="android.intent.category.LAUNCHER" />
             </intent-filter>
         </activity>
-        <activity android:name=".LoginActivity"
-            android:label="@string/activity_login_header"></activity>
+
+        <!-- Login activity -->
+        <activity
+            android:name=".LoginActivity"
+            android:label="@string/activity_login_header" />
+
+        <!-- Search user activity -->
+        <activity
+            android:name=".SearchUserActivity"
+            android:label="@string/activity_searchuser_title"/>
+
     </application>
 
 </manifest>
\ No newline at end of file
diff --git a/app/src/main/java/org/communiquons/android/comunic/client/SearchUserActivity.java b/app/src/main/java/org/communiquons/android/comunic/client/SearchUserActivity.java
new file mode 100644
index 0000000..0fef8cb
--- /dev/null
+++ b/app/src/main/java/org/communiquons/android/comunic/client/SearchUserActivity.java
@@ -0,0 +1,132 @@
+package org.communiquons.android.comunic.client;
+
+import android.os.AsyncTask;
+import android.support.annotation.Nullable;
+import android.support.v7.app.AppCompatActivity;
+import android.os.Bundle;
+import android.text.Editable;
+import android.text.TextWatcher;
+import android.util.ArrayMap;
+import android.widget.EditText;
+import android.widget.ListView;
+import android.widget.Toast;
+
+import org.communiquons.android.comunic.client.data.DatabaseHelper;
+import org.communiquons.android.comunic.client.data.UsersInfo.GetUsersHelper;
+import org.communiquons.android.comunic.client.data.UsersInfo.UsersBasicAdapter;
+import org.communiquons.android.comunic.client.data.UsersInfo.UserInfo;
+
+import java.util.ArrayList;
+
+public class SearchUserActivity extends AppCompatActivity 
+        implements TextWatcher{
+
+    /**
+     * Debug tag
+     */
+    private static final String TAG = "SearchUserActivity";
+
+    /**
+     * Search field
+     */
+    private EditText searchField;
+
+    /**
+     * Results list
+     */
+    private ListView resultListView;
+
+    /**
+     * Search result user informations
+     */
+    private ArrayList<UserInfo> resultArray;
+
+    /**
+     * Search results adapter
+     */
+    private UsersBasicAdapter resultAdapter;
+
+    /**
+     * Get user infos helper
+     */
+    private GetUsersHelper getUsersHelper;
+
+    @Override
+    protected void onCreate(Bundle savedInstanceState) {
+        super.onCreate(savedInstanceState);
+        setContentView(R.layout.activity_search_user);
+
+        //Create a get user helper object
+        getUsersHelper = new GetUsersHelper(this, DatabaseHelper.getInstance(this));
+
+        //Get view
+        searchField = (EditText) findViewById(R.id.activity_search_user_field);
+        resultListView = (ListView) findViewById(R.id.activity_search_user_results);
+
+        //Set on key listener
+        searchField.addTextChangedListener(this);
+    }
+
+    @Override
+    public void onTextChanged(CharSequence s, int start, int before, int count) {
+        //Do nothing
+    }
+
+    @Override
+    public void beforeTextChanged(CharSequence s, int start, int count, int after) {
+        //Do nothing
+    }
+
+    @Override
+    public void afterTextChanged(Editable s) {
+        newSearch(""+searchField.getText());
+    }
+
+    /**
+     * Perform a new search on the server
+     *
+     * @param query The query to perform on the server
+     */
+    private void newSearch(String query){
+
+        //Check if there is a query
+        if(query.equals(""))
+            return; //Cancel the request
+
+        new AsyncTask<String, Void, ArrayMap<Integer, UserInfo>>(){
+            @Override
+            protected ArrayMap<Integer, UserInfo> doInBackground(String... params) {
+                return getUsersHelper.search_users(params[0]);
+            }
+
+            @Override
+            protected void onPostExecute(ArrayMap<Integer, UserInfo> result) {
+                searchCallback(result);
+            }
+        }.executeOnExecutor(AsyncTask.THREAD_POOL_EXECUTOR, query);
+
+    }
+
+    /**
+     * Search callback function
+     *
+     * @param result The result of the research
+     */
+    private void searchCallback(@Nullable ArrayMap<Integer, UserInfo> result){
+
+        //Check for errors
+        if(result == null){
+            Toast.makeText(this, R.string.err_search_user, Toast.LENGTH_SHORT).show();
+            return;
+        }
+
+        //Save the results
+        resultArray = new ArrayList<>(result.values());
+
+        //Display the result
+        resultAdapter = new UsersBasicAdapter(this, resultArray);
+
+        //Set the adapter
+        resultListView.setAdapter(resultAdapter);
+    }
+}
diff --git a/app/src/main/java/org/communiquons/android/comunic/client/data/ImageLoad/ImageDownloadRunnable.java b/app/src/main/java/org/communiquons/android/comunic/client/data/ImageLoad/ImageDownloadRunnable.java
index bb4f38f..103857f 100644
--- a/app/src/main/java/org/communiquons/android/comunic/client/data/ImageLoad/ImageDownloadRunnable.java
+++ b/app/src/main/java/org/communiquons/android/comunic/client/data/ImageLoad/ImageDownloadRunnable.java
@@ -59,7 +59,7 @@ class ImageDownloadRunnable implements Runnable {
             InputStream is = conn.getInputStream();
 
             //Process image
-            Bitmap image =BitmapFactory.decodeStream(is);
+            Bitmap image = BitmapFactory.decodeStream(is);
             image.compress(Bitmap.CompressFormat.PNG, 100, os);
 
             os.close();
diff --git a/app/src/main/java/org/communiquons/android/comunic/client/data/UsersInfo/GetUsersHelper.java b/app/src/main/java/org/communiquons/android/comunic/client/data/UsersInfo/GetUsersHelper.java
index 2d1e0c9..29e476c 100644
--- a/app/src/main/java/org/communiquons/android/comunic/client/data/UsersInfo/GetUsersHelper.java
+++ b/app/src/main/java/org/communiquons/android/comunic/client/data/UsersInfo/GetUsersHelper.java
@@ -10,6 +10,7 @@ import org.communiquons.android.comunic.client.api.APIRequest;
 import org.communiquons.android.comunic.client.api.APIRequestParameters;
 import org.communiquons.android.comunic.client.api.APIResponse;
 import org.communiquons.android.comunic.client.data.DatabaseHelper;
+import org.json.JSONArray;
 import org.json.JSONException;
 import org.json.JSONObject;
 
@@ -155,6 +156,57 @@ public class GetUsersHelper {
         return usersInfo;
     }
 
+    /**
+     * Search for user from online source
+     *
+     * @param query The query string
+     * @return A list of users / false in case of failure
+     */
+    @Nullable
+    public ArrayMap<Integer, UserInfo> search_users(String query){
+
+        //Fetch users online
+        ArrayList<Integer> usersID = search_users_online(query);
+
+        //Check for errors
+        if(usersID == null)
+            return null;
+
+        return getMultiple(usersID);
+
+    }
+
+    /**
+     * Search for users on the API
+     *
+     * @param query The query of the research
+     * @return The ID of the corresponding users / false in case of failure
+     */
+    @Nullable
+    private ArrayList<Integer> search_users_online(String query){
+
+        //Make an API request
+        APIRequestParameters params = new APIRequestParameters(mContext, "search/user");
+        params.addParameter("query", query);
+
+        try {
+
+            //Get and extract the response
+            APIResponse response = new APIRequest().exec(params);
+            JSONArray array = response.getJSONArray();
+
+            //Make response
+            ArrayList<Integer> IDs = new ArrayList<>();
+            for(int i = 0; i < array.length(); i++){
+                IDs.add(array.getInt(i));
+            }
+            return IDs;
+
+        } catch (Exception e){
+            e.printStackTrace();
+            return null;
+        }
+    }
 
     /**
      * Get and return the information about multiple users from the server
diff --git a/app/src/main/java/org/communiquons/android/comunic/client/data/UsersInfo/UserInfo.java b/app/src/main/java/org/communiquons/android/comunic/client/data/UsersInfo/UserInfo.java
index 2d412c5..04cb4e0 100644
--- a/app/src/main/java/org/communiquons/android/comunic/client/data/UsersInfo/UserInfo.java
+++ b/app/src/main/java/org/communiquons/android/comunic/client/data/UsersInfo/UserInfo.java
@@ -1,5 +1,7 @@
 package org.communiquons.android.comunic.client.data.UsersInfo;
 
+import org.communiquons.android.comunic.client.data.utils.Utilities;
+
 /**
  * This class contains the informations about a single user
  *
@@ -80,6 +82,15 @@ public class UserInfo {
         return firstName + " " + lastName;
     }
 
+    /**
+     * Get the full name of the user ready to be shown
+     *
+     * @return The full name of the user
+     */
+    public String getDisplayFullName(){
+        return Utilities.prepareStringTextView(getFullName());
+    }
+
     /**
      * Set the image URL of the account of the user
      *
diff --git a/app/src/main/java/org/communiquons/android/comunic/client/data/UsersInfo/UsersBasicAdapter.java b/app/src/main/java/org/communiquons/android/comunic/client/data/UsersInfo/UsersBasicAdapter.java
new file mode 100644
index 0000000..1fd3766
--- /dev/null
+++ b/app/src/main/java/org/communiquons/android/comunic/client/data/UsersInfo/UsersBasicAdapter.java
@@ -0,0 +1,69 @@
+package org.communiquons.android.comunic.client.data.UsersInfo;
+
+import android.content.Context;
+import android.support.annotation.NonNull;
+import android.support.annotation.Nullable;
+import android.view.LayoutInflater;
+import android.view.View;
+import android.view.ViewGroup;
+import android.widget.ArrayAdapter;
+import android.widget.ImageView;
+import android.widget.TextView;
+
+import org.communiquons.android.comunic.client.R;
+import org.communiquons.android.comunic.client.data.ImageLoad.ImageLoadManager;
+import org.communiquons.android.comunic.client.data.utils.UiUtils;
+
+import java.util.ArrayList;
+import java.util.zip.Inflater;
+
+/**
+ * User basic adapter
+ *
+ * Allow to display basic informations about a set of users in a ListView
+ *
+ * @author Pierre HUBERT
+ * Created by pierre on 1/1/18.
+ */
+
+public class UsersBasicAdapter extends ArrayAdapter<UserInfo> {
+
+    /**
+     * Public constructor
+     *
+     * @param context The context of the activity
+     * @param list The dataset
+     */
+    public UsersBasicAdapter(@NonNull Context context, @NonNull ArrayList<UserInfo> list){
+        super(context, 0, list);
+    }
+
+    @NonNull
+    @Override
+    public View getView(int position, @Nullable View convertView, @NonNull ViewGroup parent) {
+
+        //Check if the view has to be inflated
+        if(convertView == null)
+            convertView = LayoutInflater.from(getContext()).
+                    inflate(R.layout.user_basic_adapter_item, parent, false);
+
+        //Get item
+        UserInfo userInfos = getItem(position);
+
+        if(userInfos != null){
+
+            //Set user name
+            ((TextView) convertView.findViewById(R.id.user_name)).
+                    setText(userInfos.getDisplayFullName());
+
+            //Set account image
+            ImageView account_image = convertView.findViewById(R.id.user_account_image);
+            ImageLoadManager.remove(account_image);
+            account_image.setImageDrawable(UiUtils.getDrawable(getContext(),
+                    R.drawable.default_account_image));
+            ImageLoadManager.load(getContext(), userInfos.getAcountImageURL(), account_image);
+        }
+
+        return convertView;
+    }
+}
diff --git a/app/src/main/java/org/communiquons/android/comunic/client/data/utils/UiUtils.java b/app/src/main/java/org/communiquons/android/comunic/client/data/utils/UiUtils.java
index fbd0227..b4a9992 100644
--- a/app/src/main/java/org/communiquons/android/comunic/client/data/utils/UiUtils.java
+++ b/app/src/main/java/org/communiquons/android/comunic/client/data/utils/UiUtils.java
@@ -1,6 +1,7 @@
 package org.communiquons.android.comunic.client.data.utils;
 
 import android.content.Context;
+import android.graphics.drawable.Drawable;
 import android.os.Build;
 
 /**
@@ -28,4 +29,14 @@ public class UiUtils {
             return context.getResources().getColor(color_id);
         }
     }
+
+    /**
+     * Get a drawable from ressources
+     *
+     * @param context The context of the application
+     * @param drawable_id The ID of the drawable to get
+     */
+    public static Drawable getDrawable(Context context, int drawable_id){
+        return context.getResources().getDrawable(drawable_id, context.getTheme());
+    }
 }
diff --git a/app/src/main/java/org/communiquons/android/comunic/client/fragments/UpdateConversationFragment.java b/app/src/main/java/org/communiquons/android/comunic/client/fragments/UpdateConversationFragment.java
index b9fbafa..335d052 100644
--- a/app/src/main/java/org/communiquons/android/comunic/client/fragments/UpdateConversationFragment.java
+++ b/app/src/main/java/org/communiquons/android/comunic/client/fragments/UpdateConversationFragment.java
@@ -1,6 +1,8 @@
 package org.communiquons.android.comunic.client.fragments;
 
+import android.app.Activity;
 import android.app.Fragment;
+import android.content.Intent;
 import android.os.Bundle;
 import android.support.annotation.Nullable;
 import android.view.LayoutInflater;
@@ -10,9 +12,11 @@ import android.widget.Button;
 import android.widget.CheckBox;
 import android.widget.ListView;
 import android.widget.TextView;
+import android.widget.Toast;
 
 import org.communiquons.android.comunic.client.MainActivity;
 import org.communiquons.android.comunic.client.R;
+import org.communiquons.android.comunic.client.SearchUserActivity;
 
 /**
  * Create and / or update a conversation fragment
@@ -23,6 +27,16 @@ import org.communiquons.android.comunic.client.R;
 
 public class UpdateConversationFragment extends Fragment {
 
+    /**
+     * Debug tag
+     */
+    private static final String TAG = "UpdateConversationFragment";
+
+    /**
+     * Find user ID intent
+     */
+    public static final int FIND_USER_ID_INTENT = 0;
+
     /**
      * The name of the conversation
      */
@@ -89,6 +103,19 @@ public class UpdateConversationFragment extends Fragment {
      */
     private void requestAddMember(){
 
+        //Make intent
+        Intent intent = new Intent(getActivity(), SearchUserActivity.class);
+        startActivityForResult(intent, FIND_USER_ID_INTENT);
+
     }
 
+    @Override
+    public void onActivityResult(int requestCode, int resultCode, Intent data) {
+        super.onActivityResult(requestCode, resultCode, data);
+
+        //Check if it is a success
+        if(resultCode == Activity.RESULT_OK){
+            Toast.makeText(getActivity(), "Request success", Toast.LENGTH_SHORT).show();
+        }
+    }
 }
diff --git a/app/src/main/res/layout/activity_search_user.xml b/app/src/main/res/layout/activity_search_user.xml
new file mode 100644
index 0000000..7cb4c5d
--- /dev/null
+++ b/app/src/main/res/layout/activity_search_user.xml
@@ -0,0 +1,28 @@
+<?xml version="1.0" encoding="utf-8"?>
+<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
+    android:layout_width="match_parent"
+    android:layout_height="match_parent"
+    android:orientation="vertical">
+
+    <!-- Enter user name -->
+    <android.support.design.widget.TextInputLayout
+        android:layout_width="match_parent"
+        android:layout_height="wrap_content">
+
+        <EditText
+            android:id="@+id/activity_search_user_field"
+            android:layout_width="match_parent"
+            android:layout_height="wrap_content"
+            android:hint="@string/activity_searchuser_text_placeholder"
+            android:maxLines="1"/>
+
+    </android.support.design.widget.TextInputLayout>
+
+    <!-- Results list -->
+    <ListView
+        android:id="@+id/activity_search_user_results"
+        android:layout_width="match_parent"
+        android:layout_height="0dp"
+        android:layout_weight="1"/>
+
+</LinearLayout>
diff --git a/app/src/main/res/layout/user_basic_adapter_item.xml b/app/src/main/res/layout/user_basic_adapter_item.xml
new file mode 100644
index 0000000..abc80ad
--- /dev/null
+++ b/app/src/main/res/layout/user_basic_adapter_item.xml
@@ -0,0 +1,23 @@
+<?xml version="1.0" encoding="utf-8"?>
+<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
+    xmlns:tools="http://schemas.android.com/tools"
+    android:orientation="horizontal"
+    android:layout_width="match_parent"
+    android:layout_height="wrap_content">
+
+    <ImageView
+        android:id="@+id/user_account_image"
+        android:layout_width="@dimen/account_image_default_width"
+        android:layout_height="@dimen/account_image_default_height"
+        android:src="@drawable/default_account_image" />
+
+    <TextView
+        android:id="@+id/user_name"
+        style="?textAppearanceListItem"
+        android:layout_width="wrap_content"
+        android:layout_height="wrap_content"
+        tools:text="User name"
+        android:layout_gravity="center"
+        android:paddingStart="5dp"
+        android:paddingEnd="1dp"/>
+</LinearLayout>
\ No newline at end of file
diff --git a/app/src/main/res/values/strings.xml b/app/src/main/res/values/strings.xml
index f0ee986..8b1457e 100644
--- a/app/src/main/res/values/strings.xml
+++ b/app/src/main/res/values/strings.xml
@@ -79,4 +79,7 @@
     <string name="fragment_update_conversation_button_create">Create</string>
     <string name="fragment_update_conversation_follow">Follow the conversation</string>
     <string name="fragment_update_conversation_addmember">Add a member</string>
+    <string name="activity_searchuser_title">Search user</string>
+    <string name="activity_searchuser_text_placeholder">User name</string>
+    <string name="err_search_user">Could not search user !</string>
 </resources>