Mailed invitations to participate in weight loss and/or smoking cessation correspondence programs to 31,400 households in a suburban community. Two programs were offered to randomized subsets of households, a 6-month correspondence program costing +5 and the same program for free but requiring a +60 deposit to be refunded based on success in weight loss or smoking cessation. Overall, sign-up included 1,304 people for weight loss and 142 for smoking cessation. The +5 program was about 5 times as popular as the incentive program. Validated weight change after 6 months averaged about 4 lb for the +5 program and 8 lb for the incentive program. Corresponding rates of smoking cessation were about 9% and 20%, respectively. We conclude that correspondence programs for the promotion of weight control and smoking cessation are potentially cost-effective methods for reaching individuals in the community at large, many of whom would not be interested in clinic-based programs. Issues meriting further research include recruitment, especially of smokers, and evaluation of the relative trade-offs in recruitment success versus efficacy of differing treatment approaches.