BACKGROUND: HIV-related stigma significantly impacts HIV care engagement, including in prevention of mother-to-child transmission of HIV (PMTCT) programs. Maisha is a stigma-based counseling intervention delivered during the first antenatal care (ANC) visit, complementing routine HIV counseling and testing. The goal of Maisha is to promote readiness to initiate and sustain treatment among those who are HIV-positive, and to reduce HIV stigmatizing attitudes among those who test negative. METHODS: A pilot randomized control trial will assess the feasibility and acceptability of delivering Maisha in a clinical setting, and the potential efficacy of the intervention on HIV care engagement outcomes (for HIV-positive participants) and HIV stigma constructs (for all participants). A total of 1000 women and approximately 700 male partners will be recruited from two study clinics in the Moshi municipality of Tanzania. Participants will be enrolled at their first ANC visit, prior to HIV testing. It is estimated that 50 women (5%) will be identified as HIV-positive. Following consent and a baseline survey, participants will be randomly assigned to either the control (standard of care) or the Maisha intervention. The Maisha intervention includes a video and counseling session prior to HIV testing, and two additional counseling sessions if the participant tests positive for HIV or has an established HIV diagnosis. A subset of approximately 500 enrolled participants (all HIV-positive participants, and a random selection of HIV-negative participants who have elevated stigma attitude scores) will complete a follow-up assessment at 3 months. Measures will include health outcomes (care engagement, antiretroviral adherence, depression) and HIV stigma outcomes. Quality assurance data will be collected and the feasibility and acceptability of the intervention will be described. Statistical analysis will examine potential differences between conditions in health outcomes and stigma measures, stratified by HIV status. DISCUSSION: ANC provides a unique and important entry point to address HIV stigma. Interventions are needed to improve retention in PMTCT care and to improve community attitudes toward people living with HIV. Results of the Maisha pilot trial will be used to generate parameter estimates and potential ranges of values to estimate power for a full cluster-randomized trial in PMTCT settings, with extended follow-up and enhanced adherence measurement using a biomarker. TRIAL REGISTRATION: ClinicalTrials.gov, NCT03600142. Registered on 25 July 2018.