Background Financial incentives promote many health behaviors, but effective ways to deliver health incentives remain uncertain. Methods We randomly assigned CVS Caremark employees and their relatives and friends to one of four incentive programs or to usual care for smoking cessation. Two of the incentive programs targeted individuals, and two targeted groups of six participants. One of the individual-oriented programs and one of the group-oriented programs entailed rewards of approximately $800 for smoking cessation; the others entailed refundable deposits of $150 plus $650 in reward payments for successful participants. Usual care included informational resources and free smoking-cessation aids. Results Overall, 2538 participants were enrolled. Of those assigned to reward-based programs, 90.0% accepted this assignment, as compared with 13.7% of those assigned to deposit-based programs (P Conclusions Reward-based programs were much more commonly accepted than deposit-based programs, leading to higher rates of sustained abstinence from smoking. Group-oriented incentive programs were no more effective than individual-oriented programs.