One of the major problems in prisons is the high rate of criminal behavior of prisoners, including aggression and pugnacity, violation of prison regulations, carrying and using illegal drugs and addictives, self-murder and self-torture, disturbance seeking, upsetting the order of prison and destruction of public property. For comparison between monotheistic integrated therapy and cognitive therapy on reduction of above-said criminal behaviors, 90 prisoners of Qom prison were randomly chosen and organized into3 groups. As experimental groups, the group’s 1 and 2 were put under monotheistic integrated therapy and cognition therapy respectively for 6 months while group 3 was left without any interference except for critical cases. For 15 days, all groups were unnoticeably put under clinical observations by trained observers both before and 2 weeks after the treatments, while their illegal behaviors were recorded on especial notes. The analysis of acquired data showed that in both treatments, the rate of criminal behavior was reduced but in monotheistic integrated therapy, the reduction was meaningfully more noticeable.