diff --git a/CHANGES.txt b/CHANGES.txt
index 793a5692e2..8c16c35b62 100644
--- a/CHANGES.txt
+++ b/CHANGES.txt
@@ -1,4 +1,5 @@
 1.2-dev
+ * enforce 1m min keycache for auto (CASSANDRA-4306)
  * remove COPP (CASSANDRA-2479)
  * Track tombstone expiration and compact when tombstone content is
    higher than a configurable threshold, default 20% (CASSANDRA-3442)
@@ -15,7 +16,6 @@
    (CASSANDRA-4293)
  * fix Summary component and caches to use correct partitioner (CASSANDRA-4289)
 
-
 1.1.1
  * add getsstables command to nodetool (CASSANDRA-4199)
  * apply parent CF compaction settings to secondary index CFs (CASSANDRA-4280)
diff --git a/src/java/org/apache/cassandra/config/DatabaseDescriptor.java b/src/java/org/apache/cassandra/config/DatabaseDescriptor.java
index 06344cc82b..7aaf0b2156 100644
--- a/src/java/org/apache/cassandra/config/DatabaseDescriptor.java
+++ b/src/java/org/apache/cassandra/config/DatabaseDescriptor.java
@@ -417,7 +417,7 @@ public class DatabaseDescriptor
             {
                 // if key_cache_size_in_mb option was set to "auto" then size of the cache should be "min(5% of Heap (in MB), 100MB)
                 keyCacheSizeInMB = (conf.key_cache_size_in_mb == null)
-                                    ? Math.min((int) (Runtime.getRuntime().totalMemory() * 0.05 / 1024 / 1024), 100)
+                                    ? Math.min(Math.max(1, (int) (Runtime.getRuntime().totalMemory() * 0.05 / 1024 / 1024)), 100)
                                     : conf.key_cache_size_in_mb;
 
                 if (keyCacheSizeInMB < 0)