Phase I obtained information on the incidence of suicides in 16,483 jails. Data were obtained not only from jail authorities but from other agencies having data on jail suicides. A total of 854 jail suicides occurred in 1985-86 (453 in 1985 and 401 in 1986). In phase II, data were received on 339 jail suicides that occurred in 1986. Data cover victims' race, sex, age, marital status, offense for which detained, confinement status, intoxication state at the time of incarceration, and the time period of the suicides. Other data cover the suicide mode, when the suicide occurred in the course of detention, and the screening procedure used for the suicide victims. Most of the findings from the present study are consistent with a similar 1981 study. Most of the key indicators -- offense, intoxication, method/instrument, isolation, and length of incarceration -- evidenced the same value over time. Experience indicates that almost all jail suicides can be averted through prevention programs that include written rules and procedures, staff training, intake screening, communication between staff, and inmate-staff interaction.