diff --git a/src/mutex.rs b/src/mutex.rs
index 28636b3..44d6cf4 100644
--- a/src/mutex.rs
+++ b/src/mutex.rs
@@ -92,6 +92,7 @@ impl<T, Lvl: IsLevel, R: RawMutex> Mutex<T, Lvl, R> {
     /// Create a new mutex with the given data.
     ///
     /// A unique [`LockId`] is assigned from a global atomic counter.
+    #[must_use]
     pub fn new(data: T) -> Self {
         Self {
             id: LockId::next(),