diff --git a/src/promise/memoize.ts b/src/promise/memoize.ts
index f8e48ee..0f452a8 100644
--- a/src/promise/memoize.ts
+++ b/src/promise/memoize.ts
@@ -24,10 +24,17 @@ function memoize<FnType extends AnyPromiseFN>(
 
   const returnFn = (async (...args: Parameters<FnType>): Promise<ThenReturn<FnType>> => {
     const key = harsher(...args);
-    if (memos.has(key)) {
-      if (!timeoutMs || Date.now() < memos.get(key)!.expiration) {
-        return memos.get(key)!.value;
-      }
+
+    if (timeoutMs) {
+      memos.forEach((item, k) => {
+        if (item.expiration > Date.now()) {
+          memos.delete(k);
+        }
+      });
+    }
+
+    if (!timeoutMs || memos.has(key)) {
+      return memos.get(key)!.value;
     }
 
     if (queues.has(key)) {