diff --git a/lib/sync.js b/lib/sync.js
index a82705b57..6fb45ccfc 100644
--- a/lib/sync.js
+++ b/lib/sync.js
@@ -338,7 +338,6 @@ SyncApi.prototype.sync = function() {
         self._getOrCreateFilter(
             getFilterName(client.credentials.userId), filter
         ).done(function(filterId) {
-            debuglog("Using existing filter ID %s", filterId);
             self._sync({ filterId: filterId });
         }, function(err) {
             self._startKeepAlives().done(function() {
@@ -702,16 +701,42 @@ SyncApi.prototype._pokeKeepAlive = function() {
  */
 SyncApi.prototype._getOrCreateFilter = function(filterName, filter) {
     var client = this.client;
+
     var filterId = client.store.getFilterIdByName(filterName);
+    var promise = q();
+
     if (filterId) {
-        // super, just use that.
-        return q(filterId);
+        // check that the existing filter matches our expectations
+        promise = client.getFilter(client.credentials.userId,
+                         filterId, true
+        ).then(function(existingFilter) {
+            var oldStr = JSON.stringify(existingFilter.getDefinition());
+            var newStr = JSON.stringify(filter.getDefinition());
+
+            if ( oldStr == newStr ) {
+                // super, just use that.
+                debuglog("Using existing filter ID %s: %s", filterId, oldStr);
+                return q(filterId);
+            }
+            debuglog("Existing filter ID %s: %s; new filter: %s",
+                     filterId, oldStr, newStr);
+            return;
+        });
     }
 
-    // create a filter
-    return client.createFilter(filter.getDefinition()).then(function(createdFilter) {
-        client.store.setFilterIdByName(filterName, createdFilter.filterId);
-        return createdFilter.filterId;
+    return promise.then(function(existingId) {
+        if (existingId) {
+            return existingId;
+        }
+
+        // create a new filter
+        return client.createFilter(filter.getDefinition()
+        ).then(function(createdFilter) {
+            debuglog("Created new filter ID %s: %s", createdFilter.filterId,
+                     JSON.stringify(createdFilter.getDefinition()));
+            client.store.setFilterIdByName(filterName, createdFilter.filterId);
+            return createdFilter.filterId;
+        });
     });
 };