Positive monetary contingencies for treating opioid dependence complicated by other drug use were examined. Participants (N = 102) entered 6-month methadone transition treatment (MTT) and were randomized into experimental conditions: 51 entered MTT with contingency contracts using monetary reinforcers and targeting abstinence from illicit drug and alcohol use, and 51 entered MTT without contingency contracts targeting abstinence. Outcomes were evaluated by random urinalysis and breath analysis. After 4 months of treatment, individuals in the contingency condition had longer periods of continuous abstinence (p<.005) and more drug-free tests overall (p<.04). Effects were limited, however, to the contracting period. The authors conclude that contingency contracting using monetary reinforcers may be a useful adjunct for achieving abstinence from multiple drugs of abuse during MTT.