Within a population of 5132 sexual offenders referred to an outpatient sexual abuse clinic, the first 100 cases receiving Medroxyprogesterone Acetate (MPA) as a long-acting intramuscular injection were retrospectively reviewed and compared to a matching cohort which did not receive the drug. MPA appeared to be a safe and effective short-term supplement to an ongoing treatment program emphasizing behavioral, cognitive, group, and family therapy approaches. Data indicate no interference with concurrent treatment approaches and no irreversible side-effects, although caution is advised regarding prolonged use of this medicine, as long term effects of MPA were not examined.These findings also help in defining the characteristics of sexual offenders who are most likely to need, and to benefit from, MPA. Those with histories of hypersexuality, poor sexual impulse control, developmental disabilities, aggressive sexuality, homosexual pedophilia, multiple paraphilias, and predatory patterns of inappropriate sexual behavior merit consideration for MPA. However, the drug should be employed as an aid, particularly early in therapy, rather than as a treatment by itself.Findings are offered with the caution that data collection and statistical analyses were relatively unsophisticated. Recommendations for further investigation are offered. Maletzky, B.M. (1991). The use of m esterone acetate to assist in the treatment of sexual offenders. Annals of Sex Research, 4,[117][118][119][120][121][122][123][124][125][126][127][128][129]