The purpose of this study is to compare voucher-based contingency management (CM) procedures to a lower-cost CM system that provides opportunities to win prizes. Cocaine-dependent outpatients are randomly assigned to (a) standard treatment, (b) standard treatment plus voucher CM for abstinence, defined by negative breath and urinalysis test results, or (c) standard treatment plus prize CM for abstinence, defined by negative breath and urinalysis test results. Urine and breath samples are collected 3x/week during Weeks 1-3, 2x/week during Weeks 4-6 and 1x/week during Weeks 7-12. Follow-up interviews are conducted 1,3,6 and 9 months following intake during which substance use and psychosocial functioning are assessed.

Inclusion criteria:

• age > 18 years
• current DSM-IV diagnosis of cocaine dependence
• maintained on a stable dose of methadone for >1 month
• willing to sign informed consent
• English speaking

Exclusion criteria:

• serious, uncontrolled psychiatric illness (e.g., acute schizophrenia, bipolar disorder, or substantial suicide risk) on the basis of history or medical examination
• dementia (<23 on the Mini Mental State Exam)
• in recovery from pathological gambling as determined by DSM-IV criteria