diff --git a/lib/verror.js b/lib/verror.js
index 1f5b5ed..0f68142 100644
--- a/lib/verror.js
+++ b/lib/verror.js
@@ -125,7 +125,7 @@ function WError(options)
 	Error.captureStackTrace(this, ctor || this.constructor);
 	this.name = name || this.constructor.name;
 	if (cause)
-		this.cause(cause);
+		WError.prototype.cause.call(this, cause);
 
 }
 mod_util.inherits(WError, Error);