A cohort of 169 opiate drug addicts was followed for 8 years. The mortality rate was 3.3 per year. The average lethality per observation year was found to be higher than in other studies. The treatment with methadone was unstable and only 11% had received stable prolonged maintenance treatment. It is not possible to reject a model that described increasing mortality rates neither as a function of falling methadone maintenance treatment nor as a function of socially unstable addicts contra stable addicts. Unemployment was high in the cohort (87%), and no relationship could be demonstrated between methadone maintenance treatment and employment.