Abstract In England and Wales, a lifetime history of mental disorder is recorded in almost a third of homicides but mental illness as a defence in homicide cases has recently come under review. In this study, we aimed to compare the social, criminological and clinical characteristics of women and men convicted of homicide and secondly, to understand how pathways through the judicial system differ by gender of the perpetrator, characteristics of the offence and mental illness. A cross sectional study of 4572 convicted homicide perpetrators in England and Wales 1997–2004 was performed. Significantly more women who had committed homicide had a lifetime history of mental illness and were more likely to be mentally ill at the time of offence compared to men. Women more often received non-custodial sentences, whether or not they had mental illness. If the victim were a child or other relative, the courts were more lenient with women. Gender and the presence of mental illness both influence the characteristics of homicide and outcome of the legal process in the UK. Our findings suggest that all perpetrators of homicide should have a psychiatric assessment pre-trial. Psychiatrists need to rate risk objectively in a gender blind way when providing psychiatric reports to be used as evidence in court.