diff --git a/Simperium/src/main/java/com/simperium/android/PersistentStore.java b/Simperium/src/main/java/com/simperium/android/PersistentStore.java
index 64f7ba6..bec2588 100644
--- a/Simperium/src/main/java/com/simperium/android/PersistentStore.java
+++ b/Simperium/src/main/java/com/simperium/android/PersistentStore.java
@@ -81,7 +81,7 @@ public void prepare(Bucket<T> bucket) {
          * Add/Update the given object
          */
         @Override
-        public void save(T object, String simperiumKey, String json, List<Index> indexes) {
+        public synchronized void save(T object, String simperiumKey, String json, List<Index> indexes) {
             mReindexer.skip(simperiumKey);
             ContentValues values = new ContentValues();
             values.put("bucket", mBucketName);