Surveys have shown that sexual offenders comprise at least 11 percent of the Federal penitentiary population and their incidence is growing. Over half the offenders in this 1979 sample had been incarcerated for rape. Sentence length for offenders with fixed sentences averaged 65.76 months, while some 9 percent were serving indeterminate life sentences. Approximately one-half were in maximum security institutions, 27 percent in medium security, and the remainder in minimum security facilities or other programs. Of the sample, 60 percent were from urban areas, and 33 percent were of Indian, Metis, or Eskimo ancestry. The intellectual capacity of many sexual offenders was limited, although case supervisors rated the group's verbal ability as slightly higher than the average offender's. Although 27 percent were married at the time of their offense, this decreased during incarceration. Persons imprisoned for a first sexual offense constituted 55.6 percent of the sample. Indecent assault was the most common previously committed sexual offense, followed by rape. Case workers judged that 67 percent of the sample needed treatment for sexual deviation. However, only 17 percent of the offenders were clearly dissatisfied with their sexual orientation, and 70 percent were not interested in participating in treatment programs in the prison setting. Male pedophiles were most likely to be discontented with their sexual lifestyle, followed by male homosexual offenders. Tables and 14 references are provided.