Background: Cardiac rehabilitation (CR) is underutilized despite demonstrated improvement to quality of life and mortality for patients with cardiovascular disease (CVD) patients. As a part of an ongoing study among an underserved urban population to improve participation in CR alongside a mobile application (app) to encourage healthful habits, we assessed CR and app perceptions among participants. Methods: We conducted in-depth open-ended interviews with a sample of patients with low socioeconomic status at Denver Health, an urban safety-net hospital with generally racially and ethnically diverse patients. We transcribed interviews and performed content analysis to identify themes. Study staff trained in qualitative methods interviewed patients on thevia phone with the goal of understanding their perceptions of CR and app use. We transcribed interviews and performed content analysis to identify themes. Results: Among 19 interviews (6 female), all patients enjoyed CR, especially the interaction with CR staff. Four patients self-identified as non-app users (1 female) vs. 15 users (5 female). Users were aged 55 years old (SD 10.4) on average, versus 66.5 years old (SD 3.4 years) among non-users. Overall 18/19 interviewees were below the poverty line in Denver for a single income household (Table). Non-users expressed reluctance around technology, and one could not recall training on app use by research study staff though they had generally higher educational status. Users identified communication with CR staff via the app as the most useful feature. Conclusion: Overall, patients liked CR, and most identified themselves as app users. Users appreciated education about healthy diet, and the ability to interact with CR staff. App users were surprisingly of lower educational status, but similar income backgrounds. This may suggest that older users among a vulnerable population require more support in accessing mobile interventions despite educational status.