Objectives: Smokers with posttraumatic stress disorder (PTSD) have increased difficulty achieving and maintaining abstinence. Contingency management approaches to smoking cessation interventions have demonstrated short-term efficacy but are limited by high rates of relapse. The goal of this pilot study was to evaluate the usability and feasibility of a smartphone-based smoking cessation application (Stay Quit Coach) designed to prevent relapse among individuals with PTSD. Methods: Smokers (N = 11) were randomized to (1) QUIT4EVER, an intervention combining mobile contingency management smoking cessation counseling and medications, and Stay Quit Coach or (2) a contact control condition that was identical to QUIT4EVER except Stay Quit Coach was not included. The primary outcome was prolonged smoking abstinence. Results: Among those queried during the follow-up periods, average Stay Quit Coach helpfulness ratings were high and ranged from 7.25 to 10 on a 10-point Likert scale (with higher scores corresponding to greater helpfulness). The Stay Quit Coach was rated by participants as being most effective at helping to quit smoking, helping to remain quit, and providing support and relevant information about quitting. Among the three quitters in the QUIT4EVER group, all reported abstinence at 3 and 6 months; however, abstinence was only bioverified for one quitter at 6 months. Among the four quitters in the contact control condition group, three reported abstinence at 3 and 6 months, but abstinence was not confirmed by bioverification. Conclusions: Smokers with PTSD express interest in and helpfulness of Stay Quit Coach for remaining abstinent after a quit attempt. Combined use of mobile contingency management and Stay Quit Coach is a feasible and acceptable adjunctive smoking cessation treatment for reducing smoking among smokers with PTSD. Adequately powered clinical trials are needed to demonstrate the long-term efficacy of this combined approach to smoking cessation. This study [Use of Technological Advances to Prevent Smoking Relapse among Smokers with PTSD (QUIT4EVER)] was registered on www. clinicaltrials. gov. clinicaltrials. gov identifier: NCT01990079.