diff --git a/CHANGES.txt b/CHANGES.txt
index 3922cb39de..93198f0131 100644
--- a/CHANGES.txt
+++ b/CHANGES.txt
@@ -14,6 +14,7 @@
  * Fix repair -snapshot not working (CASSANDRA-5512)
  * Set isRunning flag later in binary protocol server (CASSANDRA-5467)
  * Fix use of CQL3 functions with descencind clustering order (CASSANDRA-5472)
+ * Prevent repair when protocol version does not match (CASSANDRA-5523)
 Merged from 1.1
  * Add retry mechanism to OTC for non-droppable_verbs (CASSANDRA-5393)
  * Use allocator information to improve memtable memory usage estimate
diff --git a/src/java/org/apache/cassandra/service/AntiEntropyService.java b/src/java/org/apache/cassandra/service/AntiEntropyService.java
index eafab67c6a..f41089e8d8 100644
--- a/src/java/org/apache/cassandra/service/AntiEntropyService.java
+++ b/src/java/org/apache/cassandra/service/AntiEntropyService.java
@@ -668,10 +668,13 @@ public class AntiEntropyService
                     throw new IOException(message);
                 }
 
-                if (MessagingService.instance().getVersion(endpoint) < MessagingService.VERSION_11 && isSequential)
+                // All endpoints should be on the same protocol version
+                if (!MessagingService.instance().knowsVersion(endpoint) || MessagingService.instance().getVersion(endpoint) != MessagingService.current_version)
                 {
-                    logger.info(String.format("[repair #%s] Cannot repair using snapshots as node %s is pre-1.1", getName(), endpoint));
-                    return;
+                    String message = "Cannot repair among different protocol versions";
+                    differencingDone.signalAll();
+                    logger.error(String.format("[repair #%s] ", getName()) + message);
+                    throw new IOException(message);
                 }
             }