diff --git a/background.js b/background.js
index c619bcbb..ec126b20 100644
--- a/background.js
+++ b/background.js
@@ -42,7 +42,10 @@ chrome.runtime.onMessage.addListener(function (request, sender, callback) {
     //this allows the callback to be called later
     return true;
   } else if (request.message == "submitVote") {
-    submitVote(request.type, request.UUID)
+    submitVote(request.type, request.UUID, callback);
+
+    //this allows the callback to be called later
+    return true;
   }
 });
 
@@ -81,16 +84,21 @@ function addSponsorTime(time) {
   });
 }
 
-function submitVote(type, UUID) {
-  let xmlhttp = new XMLHttpRequest();
-
+function submitVote(type, UUID, callback) {
   getUserID(function(userID) {
     //publish this vote
-    console.log(serverAddress + "/api/voteOnSponsorTime?UUID=" + UUID + "&userID=" + userID + "&type=" + type);
-    xmlhttp.open('GET', serverAddress + "/api/voteOnSponsorTime?UUID=" + UUID + "&userID=" + userID + "&type=" + type, true);
-
-    //submit this vote
-    xmlhttp.send();
+    sendRequestToUser('GET', "/api/voteOnSponsorTime?UUID=" + UUID + "&userID=" + userID + "&type=" + type, function(xmlhttp) {
+      if (xmlhttp.readyState == 4 && xmlhttp.status == 200) {
+        callback({
+          successType: 1
+        });
+      } else if (xmlhttp.readyState == 4 && xmlhttp.status == 405) {
+        //duplicate vote
+        callback({
+          successType: 0
+        });
+      }
+    })
   })
 }
 
@@ -166,6 +174,19 @@ function getUserID(callback) {
   });
 }
 
+function sendRequestToUser(type, address, callback) {
+  let xmlhttp = new XMLHttpRequest();
+
+  xmlhttp.open(type, serverAddress + address, true);
+
+  xmlhttp.onreadystatechange = function () {
+    callback(xmlhttp);
+  };
+
+  //submit this request
+  xmlhttp.send();
+}
+
 function getYouTubeVideoID(url) { // Return video id or false
   var regExp = /^.*((youtu.be\/)|(v\/)|(\/u\/\w\/)|(embed\/)|(watch\?))\??v?=?([^#\&\?]*).*/;
   var match = url.match(regExp);
diff --git a/content.css b/content.css
index 3c5bfbda..763213ba 100644
--- a/content.css
+++ b/content.css
@@ -58,6 +58,13 @@
 	text-align: center;
 }
 
+#sponsorTimesErrorMessage {
+	font-size: 15px;
+	font-weight: bold;
+    color: #000000;
+	text-align: center;
+}
+
 #sponsorTimesThanksForVotingInfoText {
 	font-size: 12px;
 	font-weight: bold;
diff --git a/content.js b/content.js
index 83d4735b..2bea7df8 100644
--- a/content.js
+++ b/content.js
@@ -286,13 +286,13 @@ function openSkipNotice(){
   upvoteButton.id = "sponsorTimesUpvoteButtonsContainer" + lastSponsorTimeSkippedUUID;
   upvoteButton.className = "sponsorSkipObject voteButton";
   upvoteButton.src = chrome.extension.getURL("icons/upvote.png");
-  upvoteButton.addEventListener("click", () => upvote(UUID));
+  upvoteButton.addEventListener("click", () => vote(1, UUID));
 
   let downvoteButton = document.createElement("img");
   downvoteButton.id = "sponsorTimesDownvoteButtonsContainer" + lastSponsorTimeSkippedUUID;
   downvoteButton.className = "sponsorSkipObject voteButton";
   downvoteButton.src = chrome.extension.getURL("icons/downvote.png");
-  downvoteButton.addEventListener("click", () => downvote(UUID));
+  downvoteButton.addEventListener("click", () => vote(0, UUID));
 
   //add thumbs up and down buttons to the container
   voteButtonsContainer.appendChild(upvoteButton);
@@ -336,15 +336,7 @@ function openSkipNotice(){
   referenceNode.prepend(noticeElement);
 }
 
-function upvote(UUID) {
-  vote(1, UUID);
-
-  closeSkipNotice(UUID);
-}
-
-function downvote(UUID) {
-  vote(0, UUID);
-
+function afterDownvote(UUID) {
   //change text to say thanks for voting
   //remove buttons
   document.getElementById("sponsorTimesVoteButtonsContainer" + UUID).removeChild(document.getElementById("sponsorTimesUpvoteButtonsContainer" + UUID));
@@ -365,11 +357,41 @@ function downvote(UUID) {
   document.getElementById("sponsorTimesVoteButtonsContainer" + UUID).appendChild(thanksForVotingInfoText);
 }
 
+function votingError(message, UUID) {
+  //change text to say thanks for voting
+  //remove buttons
+  document.getElementById("sponsorTimesVoteButtonsContainer" + UUID).removeChild(document.getElementById("sponsorTimesUpvoteButtonsContainer" + UUID));
+  document.getElementById("sponsorTimesVoteButtonsContainer" + UUID).removeChild(document.getElementById("sponsorTimesDownvoteButtonsContainer" + UUID));
+
+  //add thanks for voting text
+  let thanksForVotingText = document.createElement("p");
+  thanksForVotingText.id = "sponsorTimesErrorMessage";
+  thanksForVotingText.innerText = message;
+
+  //add element to div
+  document.getElementById("sponsorTimesVoteButtonsContainer" + UUID).appendChild(thanksForVotingText);
+}
+
 function vote(type, UUID) {
   chrome.runtime.sendMessage({
     message: "submitVote",
     type: type,
     UUID: UUID
+  }, function(response) {
+    if (response != undefined) {
+      //see if it was a success or failure
+      if (response.successType == 1) {
+        //success
+        if (type == 0) {
+          afterDownvote(UUID);
+        } else if (type == 1) {
+          closeSkipNotice(UUID);
+        }
+      } else if (response.successType == 0) {
+        //failure: duplicate vote
+        votingError("It seems you've already voted before", UUID)
+      }
+    }
   });
 }
 
diff --git a/popup.js b/popup.js
index 29deaf66..cf4d54cf 100644
--- a/popup.js
+++ b/popup.js
@@ -370,7 +370,7 @@ function reportAnIssue() {
   document.getElementById("reportAnIssue").style.display = "none";
 }
 
-function vote(type, UUID) {
+function addVoteMessage(message, UUID) {
   let container = document.getElementById("sponsorTimesVoteButtonsContainer" + UUID);
   //remove all children
   while (container.firstChild) {
@@ -378,17 +378,30 @@ function vote(type, UUID) {
   }
 
   let thanksForVotingText = document.createElement("h2");
-  thanksForVotingText.innerText = "Thanks for voting!";
+  thanksForVotingText.innerText = message;
   //there are already breaks there
   thanksForVotingText.style.marginBottom = "0px";
 
   container.appendChild(thanksForVotingText);
+}
 
+function vote(type, UUID) {
   //send the vote message to the tab
   chrome.runtime.sendMessage({
     message: "submitVote",
     type: type,
     UUID: UUID
+  }, function(response) {
+    if (response != undefined) {
+      //see if it was a success or failure
+      if (response.successType == 1) {
+        //success
+        addVoteMessage("Thanks for voting!", UUID)
+      } else if (response.successType == 0) {
+        //failure: duplicate vote
+        addVoteMessage("You have already voted this way before.", UUID)
+      }
+    }
   });
 }