Smoking-cessation services are an unmet need among the homeless, who smoke at rates more than 4 times the national estimate. Successful interventions have high potential for improving tobacco-related health disparities among homeless smokers. Contingency management (CM) is a behavioral intervention with efficacy in a number of substance-use disorder populations, including smokers. However, no randomized studies have evaluated the effect of CM in homeless smokers. We examined smoking-related outcomes in homeless smokers (N = 70) randomized to standard-care (SC) smoking cessation involving transdermal nicotine-replacement therapy (NRT), standard counseling, and carbon monoxide (CO) monitoring or the same SC plus CM for negative CO sample submissions. Participants randomized to CM achieved significantly longer durations of consecutive abstinence and submitted a significantly higher proportion of CO-negative samples relative to standard-care participants. At 4 weeks postquit day, 22% were abstinent in the CM condition and 9% were abstinent in the SC condition. At the 6-month follow-up, about 10% of smokers in both conditions were abstinent. This study demonstrates that CM is an efficacious option to increase initial quit rates in homeless smokers, but methods to extend effects are needed.