OBJECTIVE: This study examined the role of workplace mandates to chemical dependency treatment in treatment adherence, alcohol and drug abstinence, severity of employment problems, and severity of psychiatric problems. METHODS: The sample included 448 employed members of a private, nonprofit U.S. managed care health plan who entered chemical dependency treatment with a workplace mandate (N=75) or without one (N=373); 405 of these individuals were followed up at one year (N=70 and N=335, respectively), and 362 participated in a five-year follow up (N=60 and N=302, respectively). Propensity scores predicting receipt of a workplace mandate were calculated. Logistic regression and ordinary least-squares regression were used to predict length of stay in chemical dependency treatment, alcohol and drug abstinence, and psychiatric and employment problem severity at one and five years. RESULTS: Overall, participants with a workplace mandate had one- and five-year outcomes similar to those without such a mandate. Having a workplace mandate also predicted longer treatment stays and improvement in employment problems. When other factors related to outcomes were controlled for, having a workplace mandate predicted abstinence at one year, with length of stay as a mediating variable. CONCLUSIONS: Workplace mandates can be an effective mechanism for improving work performance and other outcomes. Study participants who had a workplace mandate were more likely than those who did not have a workplace mandate to be abstinent at follow-up, and they did as well in treatment, both short and long term. Pressure from the workplace likely gets people to treatment earlier and provides incentives for treatment adherence.