For cellular and fixed wireless users, SMS service has been the main needs after Voice. The fast growth of SMS users especially in Telkom Flexi, in one side has created one problem for operator, that is the increasing number of criminal deception via SMS. Besides using the limited number of operator signalling canals, the criminal deception using the post-paid number will effect directly to billing fraud. This is a problem at SMSC, as SMS Center to provide the features with additional security system such as anti spamming that performs parsing, checking, and blocking on the said SMS spamming. The objective, application design, application making, analysis and evaluation on the anti spamming effect will be described in detail in this paper. It is hoped that this anti spamming implementation can decrease the numbers of the SMS criminal deception and SMS billing fraud in Telkom Flexi.