We have studied deaths occurring after release from prison in the Canton of Geneva during the period 1982-86. The mortality rate during the first year after release was about 5 deaths/1000 person years, a rate over four times the age-adjusted rate in the general population. The majority of deaths were due to overdose by opiate drugs among young, frequently imprisoned drug abusers, and occurred within the first few weeks after release. Likely risk factors include loss of tolerance to opiates while in prison, and psychological and social stresses following release.