OBJECTIVE: The authors' goal was to identify factors that increase the risk of suicide in urban jails. METHOD: They examined and verified all suicides as of 1992 in a representative large jail in Detroit since the beginning of record keeping in 1967 to 1992. RESULTS: There were 37 suicides over this time period. Inmates charged with murder or manslaughter were 19 times more likely to commit suicide than were inmates with other charges. Thirty-nine percent of the suicides were committed by individuals charged with murder. All 37 suicides were by hanging, and most occurred at night within 31 days of admission. Many of the inmates who committed suicide had made previous attempts while incarcerated. Thirty-nine percent of the suicides were committed by individuals charged with murder, constituting 2% of the admissions (two per day). CONCLUSIONS: An important risk factor in jail suicide not previously identified is the charge of murder or manslaughter. Treatment and prevention programs should recognize these inmates as belonging in a very high-risk category.