Objective: The authors' goals were to describe the characteristics of suicides committed by inmates in custody of the New York City Department of Correction between 1980 and 1988. Methods: Data on suicides were collected from records of the jail health services, the municipal medical examiner's office, and the city's prison death review board, as well as from reports of the New York State Commission of Correction and other documents. Results: The authors identified 48 suicides committed by inmates during the study period. Forty-two percent of the suicides occurred within the first 30 days of incarceration, and 50 percent occurred within three days of a court appearance. More than 90 percent of suicides were by hanging. Ninety one percent of suicides took place in cells in which the inmate was housed alone. Fifty-two percent of the inmates who committed suicide had a major psychiatric diagnosis, and 46 percent had a history of inpatient or outpatient psychiatric care. Conclusions: The authors recommend that all inmates with a psychiatric history or potential suicidality be identified and linked with ongoing mental health services while incarcerated, that potentially suicidal inmates never be housed alone in a cell, and that correctional staff be trained to recognize potentially self-destructive inmates and to prevent suicide.