diff --git a/contracts/creator-event-manager/src/event.rs b/contracts/creator-event-manager/src/event.rs
index 237757df..7b3558b5 100644
--- a/contracts/creator-event-manager/src/event.rs
+++ b/contracts/creator-event-manager/src/event.rs
@@ -55,6 +55,8 @@ pub enum EventError {
     EventCancelled = 19,
     /// entry_fee < 0
     InvalidEntryFee = 20,
+    /// Caller is not the event creator.
+    Unauthorized = 21,
 }
 
 impl From<InviteError> for EventError {
@@ -282,6 +284,48 @@ pub fn create_event(
     Ok((event_id, invite_code))
 }
 
+// ---------------------------------------------------------------------------
+// cancel_event (#1019)
+// ---------------------------------------------------------------------------
+
+/// Cancel an event. Only the event creator may call this, and only before
+/// the event has been finalized.
+///
+/// Sets `is_cancelled = true` and `is_active = false` on the stored event and
+/// emits a `("event", "cancelled")` contract event.
+///
+/// Returns [`EventError::EventNotFound`] when the ID is unknown,
+/// [`EventError::Unauthorized`] when `caller` is not the creator,
+/// and [`EventError::AlreadyFinalized`] when the event is already finalized.
+/// Returns [`EventError::EventCancelled`] if the event was already cancelled.
+pub fn cancel_event(env: &Env, caller: Address, event_id: u64) -> Result<(), EventError> {
+    caller.require_auth();
+
+    let mut event = storage::get_event(env, event_id).map_err(|_| EventError::EventNotFound)?;
+
+    if event.creator != caller {
+        return Err(EventError::Unauthorized);
+    }
+
+    if event.is_finalized {
+        return Err(EventError::AlreadyFinalized);
+    }
+
+    if event.is_cancelled {
+        return Err(EventError::EventCancelled);
+    }
+
+    event.cancel();
+    storage::set_event(env, event_id, &event);
+
+    env.events().publish(
+        (Symbol::new(env, "event"), Symbol::new(env, "cancelled")),
+        event_id,
+    );
+
+    Ok(())
+}
+
 // ---------------------------------------------------------------------------
 // get_event (#796)
 // ---------------------------------------------------------------------------
diff --git a/contracts/creator-event-manager/src/lib.rs b/contracts/creator-event-manager/src/lib.rs
index 5f2f6554..74f00d08 100644
--- a/contracts/creator-event-manager/src/lib.rs
+++ b/contracts/creator-event-manager/src/lib.rs
@@ -336,6 +336,27 @@ impl CreatorEventManagerContract {
         }
     }
 
+    /// Cancel an event. Only the event creator may call this before finalization.
+    ///
+    /// Marks the event as cancelled and inactive, and emits a
+    /// `("event", "cancelled")` contract event. Cancellation is irreversible.
+    ///
+    /// # Panics
+    /// * `"event_not_found"` — no event exists with the given ID.
+    /// * `"unauthorized"` — caller is not the event creator.
+    /// * `"already_finalized"` — the event has already been finalized.
+    /// * `"event_cancelled"` — the event is already cancelled.
+    pub fn cancel_event(env: Env, caller: Address, event_id: u64) {
+        match event::cancel_event(&env, caller, event_id) {
+            Ok(()) => {}
+            Err(EventError::EventNotFound) => panic!("event_not_found"),
+            Err(EventError::Unauthorized) => panic!("unauthorized"),
+            Err(EventError::AlreadyFinalized) => panic!("already_finalized"),
+            Err(EventError::EventCancelled) => panic!("event_cancelled"),
+            Err(_) => panic!("unexpected_error"),
+        }
+    }
+
     /// Return the escrowed prize pool (in stroops) for an event.
     ///
     /// Returns `0` for a "fun event" with no payouts.
diff --git a/contracts/creator-event-manager/tests/cancel_event_tests.rs b/contracts/creator-event-manager/tests/cancel_event_tests.rs
new file mode 100644
index 00000000..414854da
--- /dev/null
+++ b/contracts/creator-event-manager/tests/cancel_event_tests.rs
@@ -0,0 +1,164 @@
+/// Integration tests for cancel_event (#1019).
+use creator_event_manager::CreatorEventManagerContractClient;
+use soroban_sdk::testutils::Address as _;
+use soroban_sdk::testutils::Ledger;
+use soroban_sdk::token::StellarAssetClient;
+use soroban_sdk::{Address, Env, String, Vec};
+
+const FEE: i128 = 1_000_000;
+
+fn setup() -> (
+    Env,
+    CreatorEventManagerContractClient<'static>,
+    Address, // admin
+    Address, // xlm_token
+) {
+    let env = Env::default();
+    env.mock_all_auths();
+    env.ledger().with_mut(|li| {
+        li.timestamp = 1_700_000_000;
+    });
+
+    let contract_id = env.register(creator_event_manager::CreatorEventManagerContract, ());
+    let client = CreatorEventManagerContractClient::new(&env, &contract_id);
+    let client: CreatorEventManagerContractClient<'static> =
+        unsafe { core::mem::transmute(client) };
+
+    let admin = Address::generate(&env);
+    let ai_agent = Address::generate(&env);
+    let treasury = Address::generate(&env);
+    let token_admin = Address::generate(&env);
+    let xlm_token = env
+        .register_stellar_asset_contract_v2(token_admin)
+        .address();
+
+    client.initialize(&admin, &ai_agent, &treasury, &xlm_token, &FEE);
+    (env, client, admin, xlm_token)
+}
+
+fn fund(env: &Env, token: &Address, user: &Address, amount: i128) {
+    StellarAssetClient::new(env, token).mint(user, &amount);
+}
+
+/// Create a basic event and return its id.
+fn create_event(
+    env: &Env,
+    client: &CreatorEventManagerContractClient,
+    creator: &Address,
+    xlm_token: &Address,
+) -> u64 {
+    fund(env, xlm_token, creator, FEE);
+    let now = env.ledger().timestamp();
+    let (event_id, _) = client.create_event(
+        creator,
+        &String::from_str(env, "Test Event"),
+        &String::from_str(env, "A test event"),
+        &10u32,
+        &(now + 3600),
+        &(now + 7200),
+        &0i128,
+        &Vec::new(env),
+        &0i128,
+    );
+    event_id
+}
+
+// -----------------------------------------------------------------------
+// Happy path
+// -----------------------------------------------------------------------
+
+#[test]
+fn test_cancel_event_success() {
+    let (env, client, _admin, xlm_token) = setup();
+    let creator = Address::generate(&env);
+    let event_id = create_event(&env, &client, &creator, &xlm_token);
+
+    client.cancel_event(&creator, &event_id);
+
+    let event = client.get_event(&event_id);
+    assert!(event.is_cancelled);
+    assert!(!event.is_active);
+}
+
+// -----------------------------------------------------------------------
+// Guard: non-creator cannot cancel
+// -----------------------------------------------------------------------
+
+#[test]
+#[should_panic(expected = "unauthorized")]
+fn test_cancel_event_non_creator_rejected() {
+    let (env, client, _admin, xlm_token) = setup();
+    let creator = Address::generate(&env);
+    let stranger = Address::generate(&env);
+    let event_id = create_event(&env, &client, &creator, &xlm_token);
+
+    client.cancel_event(&stranger, &event_id);
+}
+
+// -----------------------------------------------------------------------
+// Guard: already-cancelled event is rejected
+// -----------------------------------------------------------------------
+
+#[test]
+#[should_panic(expected = "event_cancelled")]
+fn test_cancel_event_already_cancelled() {
+    let (env, client, _admin, xlm_token) = setup();
+    let creator = Address::generate(&env);
+    let event_id = create_event(&env, &client, &creator, &xlm_token);
+
+    client.cancel_event(&creator, &event_id);
+    client.cancel_event(&creator, &event_id); // second call must panic
+}
+
+// -----------------------------------------------------------------------
+// Guard: cancelled event blocks join_event
+// -----------------------------------------------------------------------
+
+#[test]
+#[should_panic(expected = "event_cancelled")]
+fn test_join_cancelled_event_rejected() {
+    let (env, client, _admin, xlm_token) = setup();
+    let creator = Address::generate(&env);
+    let participant = Address::generate(&env);
+    let event_id = create_event(&env, &client, &creator, &xlm_token);
+
+    let event = client.get_event(&event_id);
+    client.cancel_event(&creator, &event_id);
+    client.join_event(&participant, &event.invite_code);
+}
+
+// -----------------------------------------------------------------------
+// Guard: cancelled event blocks create_match
+// -----------------------------------------------------------------------
+
+#[test]
+#[should_panic(expected = "event_cancelled")]
+fn test_create_match_on_cancelled_event_rejected() {
+    let (env, client, _admin, xlm_token) = setup();
+    let creator = Address::generate(&env);
+    let event_id = create_event(&env, &client, &creator, &xlm_token);
+
+    client.cancel_event(&creator, &event_id);
+
+    let now = env.ledger().timestamp();
+    client.create_match(
+        &creator,
+        &event_id,
+        &String::from_str(&env, "Team A"),
+        &String::from_str(&env, "Team B"),
+        &(now + 3600),
+        &1u32,
+    );
+}
+
+// -----------------------------------------------------------------------
+// Guard: non-existent event returns event_not_found
+// -----------------------------------------------------------------------
+
+#[test]
+#[should_panic(expected = "event_not_found")]
+fn test_cancel_event_not_found() {
+    let (env, client, _admin, _xlm_token) = setup();
+    let caller = Address::generate(&env);
+    client.cancel_event(&caller, &9999u64);
+}