This article reviews the treatment history of 100 hospital-treated heroin addicts and 100 hospital-treated alcohol-dependent individuals. The two cohorts were prospectively followed for 20 and 12 years respectively and factors related to relapse and freedom from relapse were sought. Premorbid social stability, especially stable employment history, proved a more effective predictor of long-term outcome than the severity or chronicity of addiction. Inpatient treatment exerted little effect on long-term course. For both samples, encountering one or more of the following-community compulsory supervision, a substitute dependence, new relationships, and inspirational group membership-appeared associated with freedom from relapse. The challenge of preventing relapse in diabetes is offered as a useful analogy for preventing relapse in the addictions.