Thirteen of 103 patients at a methadone maintenance clinic admitted taking 33 heroin overdoses during their lives. Historical reconstruction revealed that most overdoses were covert suicide attempts. Only 12% were accidents due to variability of street samples. 38% of the covert suicide attempts were related to incarceration and the role of jail in contributing to the etiology of suicidal behavior in addicts is noted. Five cases are presented illustrating the causes of overdose in this group.