diff --git a/SDWebImageDownloader.m b/SDWebImageDownloader.m
index f1145534..81a3ae1f 100644
--- a/SDWebImageDownloader.m
+++ b/SDWebImageDownloader.m
@@ -41,7 +41,13 @@ NSString *const SDWebImageDownloadStopNotification = @"SDWebImageDownloadStopNot
     // To use it, just add #import "SDNetworkActivityIndicator.h" in addition to the SDWebImage import
     if (NSClassFromString(@"SDNetworkActivityIndicator"))
     {
+        
         id activityIndicator = [NSClassFromString(@"SDNetworkActivityIndicator") performSelector:NSSelectorFromString(@"sharedActivityIndicator")];
+
+        // Remove observer in case it was previously added.
+        [[NSNotificationCenter defaultCenter] removeObserver:activityIndicator name:SDWebImageDownloadStartNotification object:nil];
+        [[NSNotificationCenter defaultCenter] removeObserver:activityIndicator name:SDWebImageDownloadStopNotification object:nil];
+
         [[NSNotificationCenter defaultCenter] addObserver:activityIndicator
                                                  selector:NSSelectorFromString(@"startActivity")
                                                      name:SDWebImageDownloadStartNotification object:nil];