BACKGROUND: Post-traumatic stress disorder (PTSD) and alcohol use disorder (AUD) are highly prevalent, and co-occurring among post-9/11 veterans. Mobile health (mHealth) applications, specifically those focused on mindfulness-based techniques, may be an effective avenue to intervene with veterans who cannot or will not seek care at traditional in-person settings. Thus, to address areas of improvement in mHealth for veterans, we developed Mind Guide and prepared it for testing in a pilot randomized controlled trial (RCT) with veterans. METHODS: We have completed phase 1 (treatment development) and Phase 2 (beta test) of our mobile mHealth app, Mind Guide. In this paper we describe the methods for Phase 1 as well as results for our beta test (n = 16; inclusion criteria included screen for PTSD, AUD, a post-9/11 veteran, and not currently receiving treatment) for Mind Guide as well as outline procedures for our pilot RCT of Mind Guide (Phase 3). The PTSD Checklist, self-reported alcohol use, the Perceived Stress Scale, Penn Alcohol Craving Scale, and the Emotion Regulation Questionnaire were used. RESULTS: Results of our beta test of Mind Guide show promising past 30 day effects on PTSD (d = -1.12), frequency of alcohol use (d = -0.54), and alcohol problems (d = -0.44), and related mechanisms of craving (d = -0.53), perceived stress (d = -0.88), and emotion regulation (d = -1.22). CONCLUSION: Our initial beta-test of Mind Guide shows promise for reducing PTSD and alcohol related problems among veterans. Recruitment is ongoing for our pilot RCT in which 200 veterans will be recruited and followed up for 3 months. CLINICALTRIALS: gov Identifier: NCT04769986.