Objective – This paper reviews 28 studies on the epidemiology of homicide committed by mentally disordered people, taken from recent international academic literature. Methods – The studies included were identified as part of a wider systematic review of the epidemiology of offending combined with mental disorder. The main databases searched were Embase, Medline, HealthStar, Psyclit, Mental Health Abstracts, Applied Social Sciences Index and Abstracts, and Criminology Penology and Police Science Abstracts. A comprehensive search was made for studies published since 1990, supplemented with key studies from the 1980s identified through citation tracing and personal contacts. Results – A summary is given in tabular form of the content and quality of each study. There is then discussion of the studies in eight categories: descriptive studies, studies of trends, comparative studies amongst homicide offenders, amongst prisoners and including general populations, studies of homicide of relatives, follow-up studies, and studies of recidivism. Conclusions – There is an association of homicide with mental disorder, most particularly with certain manifestations of schizophrenia, antisocial personality disorder and drug or alcohol abuse. However, the quality of epidemiological research in this area is not adequate to answer key questions, and prediction of potential for homicide remains elusive. Further research is needed.