diff --git a/lib/internal/process/promises.js b/lib/internal/process/promises.js
index 1ba4aa47f575bf..b4a4582c3095a7 100644
--- a/lib/internal/process/promises.js
+++ b/lib/internal/process/promises.js
@@ -14,6 +14,8 @@ function getAsynchronousRejectionWarningObject(uid) {
 }
 
 function setupPromises(scheduleMicrotasks) {
+  let deprecationWarned = false;
+
   process._setupPromises(function(event, promise, reason) {
     if (event === promiseRejectEvent.unhandled)
       unhandledRejection(promise, reason);
@@ -73,7 +75,7 @@ function setupPromises(scheduleMicrotasks) {
         'DeprecationWarning', 'DEP0018');
     }
   }
-  var deprecationWarned = false;
+
   function emitPendingUnhandledRejections() {
     let hadListeners = false;
     while (pendingUnhandledRejections.length > 0) {