BACKGROUND: Although individuals with psychiatric disorders are disproportionately affected by cigarette smoking, few outpatient mental health treatment facilities offer smoking cessation services. In this paper, we describe the development of a smartphone-assisted mindfulness smoking cessation intervention with contingency management (SMI-CM), as well as the design and methods of an ongoing pilot randomized controlled trial (RCT) targeting smokers receiving outpatient psychiatric treatment. We also report the results of an open-label pilot feasibility study. METHODS: In phase 1, we developed and pilot-tested SMI-CM, which includes a smartphone intervention app that prompts participants to practice mindfulness, complete ecological momentary assessment (EMA) reports 5 times per day, and submit carbon monoxide (CO) videos twice per day. Participants earned incentives if submitted videos showed CO≤6ppm. In phase 2, smokers receiving outpatient treatment for mood disorders are randomized to receive SMI-CM or enhanced standard treatment plus non-contingent CM (EST). RESULTS: The results from the pilot feasibility study (N=8) showed that participants practiced mindfulness an average of 3.4times/day (≥3min), completed 72.3% of prompted EMA reports, and submitted 68.0% of requested CO videos. Participants reported that the program was helpful overall (M=4.85/5) and that daily mindfulness practice was helpful for both managing mood and quitting smoking (Ms=4.50/5). CONCLUSIONS: The results from the feasibility study indicated high levels of acceptability and satisfaction with SMI-CM. The ongoing RCT will allow evaluation of the efficacy and mechanisms of action underlying SMI-CM for improving cessation rates among smokers with mood disorders.