diff --git a/Casks/arduino-beta.rb b/Casks/arduino-beta.rb
index 639bc00e8..e8ab7bce9 100644
--- a/Casks/arduino-beta.rb
+++ b/Casks/arduino-beta.rb
@@ -4,6 +4,7 @@ class ArduinoBeta < Cask
 
   url 'http://downloads.arduino.cc/arduino-1.5.7-macosx-java7-r2.zip'
   homepage 'http://arduino.cc/'
+  license :unknown
 
   app 'Arduino.app'
 end