Abstract Introduction Contingency management (CM) is efficacious for smoking cessation. To date, the number of cost-effectiveness evaluations of behavioral and pharmacological smoking cessation treatments far outnumbers the ones on CM. This study estimated 1-year efficacy and incremental cost-effectiveness of adding CM in relation to abstinence outcomes for a cognitive-behavioral therapy (CBT)+behavioral activation (BA) treatment. Methods The study sample comprised 120 smokers with depression (% females: 70.8%; mean age: 51.67 [SD = 9.59]) enrolled in an 8-week randomized controlled clinical trial. Clinical effectiveness variables were point-prevalence abstinence, continuous abstinence, longest duration of abstinence (LDA), and Beck-Depression Inventory-II (BDI-II) scores at 1-year follow-up. Cost-effectiveness analyses were based on resource utilization, unit costs per patient, and incremental cost per additional LDA week at 1 year. Results There was a significant effect of time by treatment group interaction, which indicated superior effects of CBT+BA+CM across time. Point-prevalence abstinence (53.3% [32/60]) was superior in participants receiving CBT+BA+CM compared with those in CBT+BA (23.3% [14/60]), but both groups were equally likely to present sustained reductions in depression. The average cost per patient was €208.85 (US$236.57) for CBT+BA and €410.64 (US$465.14) for CBT+BA+CM, p < .001. The incremental cost of using CM to enhance 1-year abstinence by one extra LDA week was €18 (US$20.39) (95% confidence interval: 17.75–18.25). Conclusions Behavioral treatments addressing both smoking and depression are efficacious for sustaining high quit rates at 1 year. Adding CM to CBT+BA for smoking cessation is highly cost-effective, with an estimated net benefit of €4704 (US$5344.80). Implications Informing on the cost-effectiveness of CM might expedite the translation of research findings into clinical practice. Findings suggested that CM is feasible and highly cost-effective, confirming that its implementation is worthwhile. At a CM cost per patient of €410.64 (US$465.14), the net benefit equals €4704 (US$5344.80), although even starting from a minimum investment of €20 (US$22.72) was cost-effective. ClinicalTrials-gov Identifier NCT03163056.