diff --git a/src/main/java/org/jboss/netty/handler/codec/http/MixedAttribute.java b/src/main/java/org/jboss/netty/handler/codec/http/MixedAttribute.java
index 62a637015c..4bad8f9c03 100644
--- a/src/main/java/org/jboss/netty/handler/codec/http/MixedAttribute.java
+++ b/src/main/java/org/jboss/netty/handler/codec/http/MixedAttribute.java
@@ -73,8 +73,10 @@ public class MixedAttribute implements Attribute {
             if (attribute.length() + buffer.readableBytes() > limitSize) {
                 DiskAttribute diskAttribute = new DiskAttribute(attribute
                         .getName());
-                diskAttribute.addContent(((MemoryAttribute) attribute)
+                if (((MemoryAttribute) attribute).getChannelBuffer() != null) {
+                    diskAttribute.addContent(((MemoryAttribute) attribute)
                         .getChannelBuffer(), last);
+                }
                 attribute = diskAttribute;
             }
         }