Intravenous (IV) drug users comprise the second largest risk group for AIDS. Recent evidence indicates that IV cocaine use may present a greater risk for AIDS that IV opioid use. Although several treatments for cocaine dependence look promising, controlled studies documenting effective treatments are rare. The proposed studies will develop and validate a behavioral intervention for IV cocaine dependence. All of the studies will involve parallel-group comparisons with random assignment. The behavioral intervention consists of contingency contracting and community reinforcement of abstinence and prosocial behavior. In Study 1 this behavioral treatment will be compared to a standard psychotherapy for cocaine dependence. If the behavioral treatment is more effective than the standard treatment, a component analysis of the behavioral intervention will be conducted comparing the complete behavior intervention vs contingency contracting alone vs community reinforcement alone (Study 2a). If the behavioral treatment is not more effective than standard treatment, it will be revised to include more potent consequences in the contingency contract and compared again to the standard treatment (Study 2b). Finally, we will assess whether the efficacy of our behavioral intervention is enhanced via the addition of desipramine (Study 3). Patients will receive either the behavioral intervention plus desipramine or behavioral intervention plus placebo. All studies will be conducted in an outpatient clinic, although brief inpatient detoxifications will be conducted as needed. Duration for all treatments will be 3 months. Outcome will be measured by (1) urinalysis to validate abstinence during treatment and longer-term abstinence (6 months), (2) patient acceptability of treatment, (3) improvement in marital, family, occupational, and legal status, and (4) changes in AIDS risk behaviors. These studies will provide new information on the efficacy of behavioral interventions with cocaine dependence, demonstrate whether the efficacy of such interventions is enhanced by adding pharmacotherapy, and provide new, sorely needed treatment opportunities for IV cocaine addicts in Vermont.