The purpose of this study is to compare different forms of treatment for substance abuse. This study will involve a type of treatment called contingency management, in which patients receive incentives (prizes) for attending outpatient treatment. This study will compare contingency management to standard treatment that does not involve incentives. This study will also compare contingency management treatment that lasts 6 weeks to contingency management that lasts 12 weeks. Finally, this study will compare contingency management treatment delivered at the beginning of outpatient treatment to contingency management treatment delivered later during outpatient treatment. The investigators hypothesize that (1) a 12-week attendance-based contingency management intervention will improve retention and enhance drug abstinence versus standard treatment, (2) initial short-term exposure to attendance-based contingency management (in weeks 1-6 only) will improve substance abuse treatment outcomes compared to standard treatment alone, and (3) contingency management in weeks 7-12 will be particularly useful for those with sporadic attendance or continued drug use during initial stages of treatment.

Inclusion Criteria:

• age > 18 years
• current DSM-IV diagnosis of cocaine abuse or dependence or recent cocaine use (self-reported use in past 30 days or positive urine toxicology screen)
• willing to sign informed consent and able to pass an informed consent quiz

Exclusion Criteria:

• serious, uncontrolled psychiatric illness (e.g., acute schizophrenia, bipolar disorder, severe or psychotic major depression, or suicide risk) on the basis of history or medical examination
• in recovery from pathological gambling (meet DSM-IV criteria for lifetime pathological gambling and are actively trying to refrain from gambling)
• do not speak English (all treatment is provided in English at these clinics)