The current study is a continuation of the research into the development and evaluation of a novel treatment designed to address the chronic, persistent nature of drug addiction. This treatment, called the Therapeutic Workplace, integrates abstinence reinforcement contingencies of proven efficacy into a model supported work program. Participants were paid to work or to train in the Therapeutic Workplace but had to provide drug-free urine samples to gain daily access. Forty participants were randomly assigned to a Therapeutic Workplace or usual care control group. Therapeutic Workplace participants could work for about 5 years. This study reports the effects of the intervention over a follow-up period of 8 years after treatment initiation.