Atascadero State Hospital houses approximately 400 mentally disordered sex offenders (MDSOs). After a period of treatment, MDSOs are released back into the community at the rate of 100 to 200 individuals per year. Since the founding of the hospital in 1954, very little systematic research has been done to examine what happens to these sexual offenders once they leave the hospital. 1 In this survey, data are reported on 260 MDSOs who were released from Atascadero in 1973. Their behavior for the ensuing five years has been analyzed to provide basic descriptive data as to the general and demographic characteristics of the patients; limited data on their victims; characteristics of the offenders' hospital