ABSTRACT South Africa has the greatest burden of HIV/AIDS worldwide (19.5% adult prevalence) with approximately 8.2 million people living with HIV/AIDS (PLWHA) in 2021. Combustible cigarettes (CC) has profound health implications among PLWHA. CC smoking in PLWHA puts them at increased risk for a host of serious HIV- related co-morbidities and premature death compared to nonsmoking PLWHA. There is an urgent need for novel feasible and efficacious strategies for CC cessation and harm reduction addressing these challenges among PLWHA in general, and in South Africa in particular. This proposal aims to address the unmet need for feasible and efficacious strategies for reducing CC use among PLWHA in South Africa, which has the potential to significantly improve the health and long-term survival of PLWHA CC smokers. The proposed intervention is based on the Information-Motivation-Behavioral Skills (IMB) model, and informed by our ongoing research. Using a simultaneous embedded mixed methods approach, we will evaluate a telehealth program targeting CC harm reduction, comparing E-cigarettes (EC) to nicotine replacement therapy (NRT) that is enhanced by integrating ecological momentary intervention (EMI) texting. As such, this proposal will significantly build research capacity in South Africa to conduct telehealth tobacco treatment interventions using innovative EMI approaches enhancing participants’ engagement, as well as state-of-the art evaluation approaches. The Specific Aims are to: 1) Adapt an existing telehealth intervention for CC harm reduction to the South African context, and 2) Determine the feasibility and acceptability of adapted intervention (primary outcomes), and Estimate and Compare the preliminary effects of EC and NRT on CC reduction (secondary outcomes) using a pilot randomized controlled trial (RCT) design. We will adapt an existing CC harm reduction protocol. Recruiting PLWHA smokers from eight healthcare facilities in the Western Cape in South Africa providing ART to PLWHA, we will refine and finalize the intervention to be evaluated in a pilot RCT 3-group design (N=90). Arm 1 (Control): Referral to quit-line; Arm 2: Telephone counseling + EMI + combination NRT (patch + lozenge); Arm 3: Telephone counseling + EMI + EC. Consistent with a pilot RCT, primary outcomes will be: A) Feasibility of the intervention as defined by Recruitment, completion, and follow-up rates, and B) Acceptability as assessed by the Client Satisfaction Questionnaire and interviews. Secondary outcomes include 1) IMB theory-based mechanisms of change, 2) proportion of CC smokers achieving 7-day point prevalence abstinence, verified by exhaled carbon monoxide (<6 ppm) at 3- and 6-months, 3) reductions in cigarettes per day compared to baseline, and 4) changes in health outcomes. This proposal will build capacity and lay the groundwork to help decrease CC smoking among PLWHA in South Africa.