diff --git a/lib/SimpleSAML/MemcacheStore.php b/lib/SimpleSAML/MemcacheStore.php
index 74d4d13c885254cee268726a4eab64067647166e..35a77a25888a3a3b17ffdcea8a9b00c5b2a5dc8d 100644
--- a/lib/SimpleSAML/MemcacheStore.php
+++ b/lib/SimpleSAML/MemcacheStore.php
@@ -145,7 +145,7 @@ class SimpleSAML_MemcacheStore {
 		 * we need to update this object, then we don't store the
 		 * serialized value.
 		 */
-		if($mustUpdate === TRUE) {
+		if($mustUpdate === FALSE) {
 			$latest->savedData = $latestSerializedValue;
 		}