A randomized study is planned to evaluate the effectiveness of employment-based reinforcement in promoting depot naltrexone adherence in opiate-dependent adults. Vivitrol, an extended-release depot formulation of naltrexone approved by the FDA for the treatment of alcohol dependence, will be used. Participants will be offered an inpatient opioid detoxification and oral naltrexone induction. Participants who complete the oral naltrexone induction (N=40) will be randomly assigned to one of two groups. Both groups will be invited to work in the Therapeutic Workplace and will be prescribed depot naltrexone for 6 months. Participants in the "Work Plus Naltrexone Contingency" condition will earn access to working and earning salary by taking depot naltrexone injections once per month. "Work Plus Naltrexone Prescription" participants will be encouraged to take depot naltrexone monthly, but access to working and earning salary will not be contingent on doing so.