Abstract The study assessed the effects of contingency contracting for medication take- home privileges on the polydrug use of methadone patients. Comparisons were made among 20 patients using cocaine, 13 using other illicit drugs, and seven exhibiting other non- compliant behavior. A within-subjects reversal design showed that there was no overall difference in the percentage of positive urines between the pre-contingency and contingency periods, nor between the pre-and post-contingency periods. During the first contingency month, however, one group of patients eliminated drug use, while the remaining had an increased percentage of positive urines. This increase may have been due to the heightened urinalysis regimen during the contingency period rather than to more actual drug use. During the first month, drug-related contracts not involving cocaine were more successful than those targeting cocaine, and non-drug-related contracts were more successful than drug- related ones. The study concluded that contracting had a favorable, though transient, effect primarily on non-cocaine-abusing methadone patients. Further research using stronger or multiple reinforcers is indicated.