Machiavellianism is a system of beliefs combining a cynical view of human nature that represents people as weak, cowardly, selfish, and easily misled, with a willingness to use manipulative tactics that take advantage of this weakness, and with disrespect for conventional morality. The behavioral patterns typical of people that endorse these beliefs to an above average extent are called high Machs, and those that reject them are called low Machs. High Machs are characterized by a cool, cognitive analysis of interpersonal situations that enables them to resist social influences and to initiate and create structure. Low Machs are empathically enmeshed in the feelings and desires of other people so that they are susceptible to social influence, and inclined to accept and follow the structures projected by others. It is hypothesized that men that sexually abuse children repetitively will tend to be rated higher on Machiavellianism. A sample of 157 adult male child molesters was extracted from the database of a national sex offender treatment program. The analysis compared the Machiavellianism scores of those child molesters that had been sentenced on a single occasion for this kind of offense to those that had been sentenced on two or more occasions. The results showed that more repetitive child molesters do seem to be more inclined to endorse general Machiavellian beliefs. The mean Machiavellianism score of those child molesters that went on to be sexually reconvicted was much higher than those that were not reconvicted. This gives some credibility to the proposed link between Machiavellian beliefs and repeated sexual offending. Treatment programs ought to assess for generalized Machiavellian beliefs and should target them for change. Machiavellian beliefs should be included in the range of psychological factors assessed in comprehensive systems designed to assess the risk presented by sexual offenders. Processes for managing and supervising sexual offenders in the community need to take account of the likely vulnerability of low Mach supervisors to high Mach offenders. 3 tables, 1 note, 8 references