Mental health service provision by social workers in a county jail is examined through a retrospective review of 359 mentally ill jail inmates' health and mental health records. Length of stay and number of service episodes are compared by crime, gender, race, and psychiatric disorder. Male inmates stayed on the mental health unit significantly longer and inmates with psychotic disorders had significantly more service episodes. Of the non-psychiatric, mental health services provided beyond initial assessment, housing placement evaluations and follow-up sessions were the most frequent. Suggestions for ongoing service efforts, with an emphasis on release planning, are made.