PurposeBy 2020, 70% of people living with HIV in the United States will be greater than 50 years of age. As many as 37% of sexually active older people living with HIV (OPLWH) engage in HIV transmission sexual behaviors. In spite of repeated calls for secondary prevention interventions to reduce condomless sex in OPLWH, no age-appropriate, evidence-based secondary prevention interventions exist for this group. Furthermore, many OPLWH face barriers to engaging in face-to-face secondary prevention services because of HIV- and age-related stigma, comorbid mental and physical health conditions that complicate travel, or geographic isolation. High rates of depression in OPLWH may further complicate engagement in interventions intended to reduce HIV transmissions. Telephone-administered motivational interviewing may be a feasible and efficacious intervention for this population. MethodsThis randomized controlled trial will test the efficacy of a 5-session telephone-administered motivational interviewing plus behavioral skills training (teleMI+BST) intervention versus a 5-session telephone-administered coping effectiveness training (teleCET) control intervention to reduce condomless sex in OPLWH. A diverse sample of 336 OPLWH will be recruited across the U.S. The primary analysis will test the efficacy of teleMI+BST to reduce occasions of non-condom protected anal and vaginal intercourse with HIV serodiscordant sex partners. Secondary analyses will examine the efficacy of teleMI+BST to reduce depressive symptoms in mildly depressed OPLWH. ConclusionThis is the first large-scale RCT intended to reduce HIV sexual transmission risk behavior in OPLWH and will add to the literature on secondary prevention telehealth interventions for people living with HIV.ClinicalTrials.gov Identifier: NCT03004170. This trial has been conducted by the approval of the Institutional Review Board. Participants provided verbal consent to participate in this trial.