Kleptomania is one of the psychological disorders which make a patient rob objects. Based on the high rate and hidden feature of this disorder, reviewing the criminal liability of these patients are so important in criminal law and it faces with lots of vagueness. Reaching this aim, first of all, the most important features of this disorder and then the discretion and his psychological situation in the time of theft will be considered by this paper. Furthermore, it scrutinizes the effect of this disorder as an excuse or mitigating factor and concludes that despite the fact that Kleptomania is an acute psychological disease, it cannot be considered as an excuse but mitigating factor.