The aim of this article is to describe the social, relational and mental health characteristics of a sample of offenders serving prison or community sentences in the south-west England. About 100 adult male offenders were screened for anxiety and depressive disorders, post-traumatic stress disorder (PTSD), drug and alcohol dependence, and likely personality disorder using validated instruments. Fifty-eight per cent of the sample reported at least one common mental health problem, of these only 26% reported receiving treatment. Participants exposed to traumatic events and/or participants with past mental health problems were more likely to score positive for current common mental health problems. Our study identified factors that may increase the risk of a first episode or recurrent anxiety and/or depression for offenders. Health and criminal justice services should create partnerships and develop interventions that address the risk factors which lead and/or contribute to offenders' mental health difficulties.