The development of empirically supported behavioral and cognitive behavioral strategies for the treatment of cocaine abuse disorders is an important addiction research priority. This application proposes two studies which will evaluate two promising approaches, relapse prevention (RP) and contingency management (CM), for the treatment of cocaine abuse with two populations. Study 1 will compare RP and CM, alone and in combination, for the treatment of primary cocaine abusers. One hundred eighty (180) cocaine abusers will be randomly assigned into one of 3 groups with either an RP procedure (n=60), a CM procedure (n=60) or a combination of RP and CM procedures (n=60). The RP condition will consist of three RP sessions per week for 12 weeks followed by two RP sessions per week for an additional 12 weeks. The CM program will involve an identical schedule of clinic visits as the RP condition. The CM procedure will involve the establishment of a graduated system of positive reinforcement vouchers delivered to Ss upon achievement of cocaine negative urine samples. Study 2 will compare RP and CM alone and in combination as treatment methods for cocaine-abusing methadone patients. The design of this study will be a 2x2 (RP by CM), with treatment cells consisting of the 3 conditions described in study 1 and, in addition, a condition which involves methadone maintenance treatment as usual, with no specific intervention for cocaine abuse. Two hundred (200) cocaine-abusing methadone patients will be randomly assigned to one of four treatment conditions (n=50 per condition). In both studies, the following types of data will be collected; Demographic information and drug use history; psychiatric diagnosis (SCID); measure of treatment motivation and readiness (CMRS); self report of drug and alcohol use (time line followback); multidimensional behavior change measure (ASI); a measure of prosocial behavior change (BCI); physical measures of drug and alcohol use (urinalysis and breathalcohol results); HIV risk behaviors; retention rates in treatment; composite score of treatment effectiveness (TES). The two studies will greatly expand the knowledge on the value of RP and CM for the treatment of cocaine abuse with two important cocaine-abusing population.