Exacerbated by life stressors, fatigue is the most common symptom for people living with HIV.To adapt, develop, and assess the feasibility of a CBSM mHealth (cognitive behavioral stress management mobile health) application (app) for HIV-related fatigue.This study had two phases: app development with key informants (N=5) and a randomized controlled trial (N=30). Patients randomized to the intervention group completed 10 weekly CBSM modules; those in the control group received a generic healthy lifestyle app. Measures included HIV-related fatigue, depression, anxiety, stressful life events, CD4 count, HIV viral load, credibility and acceptability of the intervention, and barriers to treatment participation.We were able to recruit participants for this study, and they were able to complete the required measures. They found the intervention to be credible and acceptable, and reported few barriers to treatment participation. The direction of change in the primary outcome, a decrease in fatigue, is in the expected direction, and provides evidence of the promise of the intervention, which still needs to be tested in an adequately powered trial. For completers (randomized to the intervention group and completed at least 80% of the modules), there were significant changes (95% CI; lower scores indicate improvement) in fatigue intensity (from 64.2 to 59.7) and overall fatigue-related functioning (from 6.6 to 4.2).We have proof of concept as to the feasibility, acceptability, and initial signals of efficacy for an mHealth intervention to help people with HIV-related fatigue better cope with stress and reduce their fatigue.