diff --git a/include/sys/atomic.h b/include/sys/atomic.h
index 69b8193cdae..7de01e44058 100644
--- a/include/sys/atomic.h
+++ b/include/sys/atomic.h
@@ -49,11 +49,11 @@ static inline bool atomic_cas(atomic_t *target, atomic_val_t old_value,
 					   __ATOMIC_SEQ_CST);
 }
 #elif defined(CONFIG_ATOMIC_OPERATIONS_C)
-__syscall int atomic_cas(atomic_t *target, atomic_val_t old_value,
+__syscall bool atomic_cas(atomic_t *target, atomic_val_t old_value,
 			 atomic_val_t new_value);
 
 #else
-extern int atomic_cas(atomic_t *target, atomic_val_t old_value,
+extern bool atomic_cas(atomic_t *target, atomic_val_t old_value,
 		      atomic_val_t new_value);
 #endif
 
diff --git a/kernel/atomic_c.c b/kernel/atomic_c.c
index 15d42d0f410..56797e9f546 100644
--- a/kernel/atomic_c.c
+++ b/kernel/atomic_c.c
@@ -63,10 +63,10 @@ static struct k_spinlock lock;
  *
  * This routine provides the compare-and-set operator. If the original value at
  * <target> equals <oldValue>, then <newValue> is stored at <target> and the
- * function returns 1.
+ * function returns true.
  *
  * If the original value at <target> does not equal <oldValue>, then the store
- * is not done and the function returns 0.
+ * is not done and the function returns false.
  *
  * The reading of the original value at <target>, the comparison,
  * and the write of the new value (if it occurs) all happen atomically with
@@ -75,19 +75,19 @@ static struct k_spinlock lock;
  * @param target address to be tested
  * @param old_value value to compare against
  * @param new_value value to compare against
- * @return Returns 1 if <new_value> is written, 0 otherwise.
+ * @return Returns true if <new_value> is written, false otherwise.
  */
-int z_impl_atomic_cas(atomic_t *target, atomic_val_t old_value,
-		      atomic_val_t new_value)
+bool z_impl_atomic_cas(atomic_t *target, atomic_val_t old_value,
+		       atomic_val_t new_value)
 {
 	k_spinlock_key_t key;
-	int ret = 0;
+	int ret = false;
 
 	key = k_spin_lock(&lock);
 
 	if (*target == old_value) {
 		*target = new_value;
-		ret = 1;
+		ret = true;
 	}
 
 	k_spin_unlock(&lock, key);
@@ -96,8 +96,8 @@ int z_impl_atomic_cas(atomic_t *target, atomic_val_t old_value,
 }
 
 #ifdef CONFIG_USERSPACE
-int z_vrfy_atomic_cas(atomic_t *target, atomic_val_t old_value,
-		      atomic_val_t new_value)
+bool z_vrfy_atomic_cas(atomic_t *target, atomic_val_t old_value,
+		       atomic_val_t new_value)
 {
 	Z_OOPS(Z_SYSCALL_MEMORY_WRITE(target, sizeof(atomic_t)));
 
diff --git a/tests/kernel/common/src/atomic.c b/tests/kernel/common/src/atomic.c
index a4e475b06fd..abba01f682e 100644
--- a/tests/kernel/common/src/atomic.c
+++ b/tests/kernel/common/src/atomic.c
@@ -34,9 +34,9 @@ void test_atomic(void)
 	oldvalue = 6;
 
 	/* atomic_cas() */
-	zassert_true((atomic_cas(&target, oldvalue, value) == 0), "atomic_cas");
+	zassert_false(atomic_cas(&target, oldvalue, value), "atomic_cas");
 	target = 6;
-	zassert_true((atomic_cas(&target, oldvalue, value) == 1), "atomic_cas");
+	zassert_true(atomic_cas(&target, oldvalue, value), "atomic_cas");
 	zassert_true((target == value), "atomic_cas");
 
 	/* atomic_add() */