Four English special hospitals provide for the secure treatment of serious offenders. Between 1961 and 1965, there were 1,046 male admissions to these special hospitals, involving 1,001 different offenders (45 men had more than one admission). The case notes of these patients were examined to obtain information on the circumstances of admission, current and past social status, past and present psychiatric diagnosis, treatment, and criminal behavior. In 1970 and in 1979, followup information was obtained from the special hospitals to determine whether the persons had been discharged during this time, from the criminal record office regarding any subsequent offending, from the mental health enquiry regarding subsequent mental hospitalization, and from the National Health Service Register to determine any deaths and causes of deaths among the sample. Data were obtained on 617 of the men. Of those who spent time in the community (an average of 8.8 years) after discharge, 55 percent committed some offense during the followup period; however, only 21 percent committed a violent offense. Members of the offender groups had more previous convictions, younger ages at previous convictions, more time in institutions, and generally more unsettled backgrounds than members of the nonoffending group. The violent offenders differed from the nonviolent offenders in the number of court appearances after discharge, a preadmission history of multiple violence, having a juvenile institutional record, and being transferred to the special hospital from prison or from other hospitals. Tabular data and 10 references are provided.