The growth of online game development now a day makes us have to be more careful in doing trade or transactions inside the game. A transactions in the virtual world today is filled with virtual crime which known as cyber crime. Common cyber crime in online games is fraud related to virtual goods or usually referred to the item mall [4]. In this study, the authors tried to suggest a method for prevention of fraud within transactions in the online game by tracing the phone number which been use from the form registration for online gaming. Analysis of this case is done by using the rules of the applicable rules in Indonesia is the ITE Law No. 11 of 2008 and Article 378 of the Criminal Code.