diff --git a/geneit_backend/src/controllers/accommodations_reservations_controller.rs b/geneit_backend/src/controllers/accommodations_reservations_controller.rs
index 67469fb..afee380 100644
--- a/geneit_backend/src/controllers/accommodations_reservations_controller.rs
+++ b/geneit_backend/src/controllers/accommodations_reservations_controller.rs
@@ -146,3 +146,51 @@ pub async fn delete(m: FamilyAndAccommodationReservationInPath) -> HttpResult {
 
     Ok(HttpResponse::Accepted().finish())
 }
+
+#[derive(serde::Deserialize)]
+pub struct ValidateQuery {
+    validate: bool,
+}
+
+/// Validate or reject a reservation
+pub async fn validate_or_reject(
+    m: FamilyAndAccommodationReservationInPath,
+    q: web::Json<ValidateQuery>,
+) -> HttpResult {
+    if !m.membership().is_admin {
+        return Ok(HttpResponse::BadRequest().json("Only an admin can validate a reservation!"));
+    }
+
+    if m.validated == Some(q.validate) {
+        return Ok(
+            HttpResponse::AlreadyReported().json("This reservation has already been processed!")
+        );
+    }
+
+    // In case of re-validation, check that the time is still available
+    if m.validated == Some(false) && q.validate {
+        let potential_conflicts =
+            accommodations_reservations_service::get_reservations_for_time_interval(
+                m.accommodation_id(),
+                m.reservation_start as usize,
+                m.reservation_end as usize,
+            )
+            .await?;
+
+        if potential_conflicts
+            .iter()
+            .any(|a| a.validated != Some(false))
+        {
+            return Ok(HttpResponse::Conflict().json(
+                "This cannot be accepted as it would create a conflict with another reservation!",
+            ));
+        }
+    }
+
+    // Update reservation validation status
+    let mut reservation = m.to_reservation();
+    reservation.validated = Some(q.validate);
+    accommodations_reservations_service::update(&mut reservation).await?;
+
+    Ok(HttpResponse::Accepted().finish())
+}
diff --git a/geneit_backend/src/main.rs b/geneit_backend/src/main.rs
index 5799638..0de9626 100644
--- a/geneit_backend/src/main.rs
+++ b/geneit_backend/src/main.rs
@@ -252,7 +252,10 @@ async fn main() -> std::io::Result<()> {
                 "/family/{id}/accommodations/reservation/{reservation_id}",
                 web::delete().to(accommodations_reservations_controller::delete),
             )
-            // TODO : validate or reject
+            .route(
+                "/family/{id}/accommodations/reservation/{reservation_id}/validate",
+                web::post().to(accommodations_reservations_controller::validate_or_reject),
+            )
             // [ACCOMMODATIONS] Calendars controller
             // TODO : create
             // TODO : list