This study examines the extent to which severely mentally disabled (SMD) patients in one county mental health system were incarcerated in the local jail and examines characteristics of a sample (N = 30) of such individuals. We found that in the study year, 7.9% of known SMD patients had at least one incarceration in the county jail. Diagnoses were predominantly in the schizophrenia spectrum with 70% also actively abusing substances at the time of incarceration. The majority of crimes were non-violent and substance abuse related. Half of the sample was judged to be candidates for diversion programs. Our findings are consistent with recent literature confirming that substance abusing SMD individuals are at high risk of incarceration and could benefit from integrated mental health and substance abuse treatment.