Background: Early findings from a national study of discharges from 32 National Health Service medium secure units revealed that nearly twice as many patients than expected were discharged back to prison. Aims: To compare the characteristics of those discharged back to prison with those discharged to the community, and consider the implications for ongoing care and risk. Method: Prospective cohort follow-up design. All forensic patients discharged from 32 medium secure units across England and Wales over a 12-month period were identified. Those discharged to prison were compared with those who were discharged to the community. Results: Nearly half of the individuals discharged to prison were diagnosed with a serious mental illness and over a third with schizophrenia. They were a higher risk, more likely to have a personality disorder, more symptomatic and less motivated than those discharged to the community. Conclusions: Findings suggest that alternative models of prison mental healthcare should be considered to reduce risks to the patient and the public.