Objective: We observed a pattern of combining depot antipsychotic medication with the newer 'atypical' antipsychotics in forensic patients. We aimed to determine the prevalence and rationale for such 'combination therapy'. Method: The medical records of forensic patients in 3 forensic hospitals in New South Wales, Australia, were reviewed and the responsible psychiatrists asked to explain the rationale for treatment of those patients on combination therapy. Results: Twenty-two per cent of the forensic patient population were receiving combination therapy. The reasons given for combination therapy were the presence of treatment-resistant illness, to ensure adherence to at least part of the treatment and to assist transfer to lower security units. Conclusions: Such a high prevalence of a practice that is discouraged and without theoretical justification is a cause for concern. It appeared to reflect the practical difficulties of managing forensic patients.