An overview of the literature on this topic focuses on sex offenders' use of pornography for self-stimulation, to groom the victims, and for later self-gratification and monetary gain. The current study involved a sample of 124 cases (Sample 1) from the authors' private practice; in every case, the offenders were asked about their use of pornography and its role in their sex offenses. Police reports were also available in the majority of cases and were used in interviews with the offenders. In order to examine whether trends in the use of pornography by sex offenders has changed over the past 30 years, a historical sample of 437 cases was drawn from a database of 2,125 sex-offender cases collected from 1970 to 1991 at the Clarke Institute of Psychiatry (Sample 2). Of the 561 cases studied, only 17 percent involved the use of pornography immediately prior to or during the offense. These findings suggest that the mere possession of pornography does not in itself lead to the commission of a sexual crime. Although 47 percent of the offenders had pornography in their possession prior to their crimes, only 17 percent used it for self-stimulation either immediately prior to the crime or during the crime. Offenders against children used pornography more than offenders against adults (42 percent compared with 19 percent). There was no indication of a change in patterns of pornography over time in Sample 2; however, the increased availability of pornography through the Internet may change this pattern in the foreseeable future. 3 tables and 30 references