diff --git a/asb-ballerina/message.bal b/asb-ballerina/message.bal
index ae17c326..9769e02a 100644
--- a/asb-ballerina/message.bal
+++ b/asb-ballerina/message.bal
@@ -35,7 +35,7 @@ public type Message record {|
     @display {label: "Body"}
     string|xml|json|byte[] body;
     @display {label: "Content Type"}
-    string contentType?;
+    string contentType = TEXT;
     @display {label: "Message Id"}
     string messageId?;
     @display {label: "To"}