Research demonstrates that injection drug users with HIV and/or AIDS have difficulty adhering to complex regimens of HIV medications. Because of the risk of increased viral resistance associated with irregular medication adherence, there is considerable clinical need to assist clients who abuse substances in taking their antiretroviral medications on time and as directed. This article outlines intervention strategies to improve medication adherence among clients who are in methadone maintenance. In this treatment manual, the authors delineate contingency management procedures, including voucher incentives and a fishbowl lottery prize system. They also describe intervention elements and adherence tools for medication coaching. The purpose of this manual is to describe the intervention procedures for clinicians and to serve as a resource for drug abuse treatment programs that serve clients who are HIV-positive. (Contains 4 tables and 1 note.)