diff --git a/src/main/java/net/openhft/chronicle/map/serialization/impl/LongMarshaller.java b/src/main/java/net/openhft/chronicle/map/serialization/impl/LongMarshaller.java
index 2506058e9..0ad365acf 100644
--- a/src/main/java/net/openhft/chronicle/map/serialization/impl/LongMarshaller.java
+++ b/src/main/java/net/openhft/chronicle/map/serialization/impl/LongMarshaller.java
@@ -25,7 +25,7 @@ public enum LongMarshaller implements AgileBytesMarshaller<Long> {
 
     @Override
     public long size(Long e) {
-        return 4L;
+        return 8L;
     }
 
     @Override
@@ -55,7 +55,7 @@ public enum LongMarshaller implements AgileBytesMarshaller<Long> {
 
     @Override
     public long readSize(Bytes bytes) {
-        return 4L;
+        return 8L;
     }
 
     @Override