diff --git a/src/iframeResizer.js b/src/iframeResizer.js
index 4ea1d309a..754a2a78e 100644
--- a/src/iframeResizer.js
+++ b/src/iframeResizer.js
@@ -13,6 +13,7 @@
   if (typeof window === 'undefined') return // don't run for server side render
 
   var count = 0,
+    destroyObserver,
     logEnabled = false,
     hiddenCheckEnabled = false,
     msgHeader = 'message',
@@ -729,6 +730,10 @@
     chkEvent(iframeId, 'onClosed', iframeId)
     log(iframeId, '--')
     removeIframeListeners(iframe)
+    if (destroyObserver) {
+      destroyObserver.disconnect()
+      destroyObserver = null  
+    }
   }
 
   function getPagePosition(iframeId) {
@@ -1130,7 +1135,7 @@
 
       function createDestroyObserver(MutationObserver) {
         if (!iframe.parentNode) {
-          return
+          return null
         }
 
         var destroyObserver = new MutationObserver(function (mutations) {
@@ -1146,11 +1151,12 @@
         destroyObserver.observe(iframe.parentNode, {
           childList: true
         })
+        return destroyObserver
       }
 
       var MutationObserver = getMutationObserver()
       if (MutationObserver) {
-        createDestroyObserver(MutationObserver)
+        destroyObserver = createDestroyObserver(MutationObserver)
       }
 
       addEventListener(iframe, 'load', iFrameLoaded)