diff --git a/makefiles/deprecated_modules.inc.mk b/makefiles/deprecated_modules.inc.mk
index 84f29e0a7c..13973e94c5 100644
--- a/makefiles/deprecated_modules.inc.mk
+++ b/makefiles/deprecated_modules.inc.mk
@@ -3,3 +3,4 @@
 DEPRECATED_MODULES += event_thread_lowest
 DEPRECATED_MODULES += gnrc_netdev_default
 DEPRECATED_MODULES += sema_deprecated
+DEPRECATED_MODULES += ztimer_now64
diff --git a/sys/include/ztimer.h b/sys/include/ztimer.h
index 8f9fc37863..4c4ffb3394 100644
--- a/sys/include/ztimer.h
+++ b/sys/include/ztimer.h
@@ -302,9 +302,11 @@ struct ztimer_base {
 };
 
 #if MODULE_ZTIMER_NOW64
-typedef uint64_t ztimer_now_t;  /**< type for ztimer_now() result */
+typedef uint64_t ztimer_now_t;  /**< type for ztimer_now() result
+                                 * @deprecated use uint32_t or ztimer64 */
 #else
-typedef uint32_t ztimer_now_t;  /**< type for ztimer_now() result */
+typedef uint32_t ztimer_now_t;  /**< type for ztimer_now() result
+                                 * @deprecated use uint32_t or ztimer64 */
 #endif
 
 /**