Approximately 1.33 million pregnancies are recorded in South Africa annually. About 30% of all pregnant women are HIV positive, posing a serious risk to unborn children. However, effective interventions such as prevention of mother-to-child transmissions (PMTCT) services have been shown to significantly reduce the risk of mother-to-child or vertical transmission. Migrant women in South Africa face challenges in accessing [free] healthcare services. This study aims to assess the cost-effectiveness of providing free PMTCT services to migrant women living in South Africa. We employed cost-effectiveness analysis methodology to establish the cost and outcomes (averted pediatric infections and averted disability-adjusted life years (DALYs)) associated with free PMTCT services for migrant women. The comparator was provision of only antenatal care (ANC) while the intervention was ANC + PMTCT services. A Microsoft Excel-based decision tree model was designed to achieve the study objectives. Data on costs and health outcomes for each intervention was sourced from the literature on HIV/AIDS. The prevalence-based study is conducted from a public sector healthcare payer perspective. Provision of ANC + PMTCT services to migrants will prevent 14 562 new infections among 52 762 HIV positive pregnant women. The estimated total expected cost of ANC + PMTCT service was US2 889 per 1000 live births compared to US91 000 for ANC only per 1000 live births. The expected cost for the do-nothing scenario was US3 535 per 1000 live births. The expected health benefit (ie, averted DALYs) associated with do-nothing scenario, ANC, and ANC + PMTCT were 277, 265 and 76 DALYs, respectively. ANC + PMTCT service provision produces the lowest DALYs at lower cost thereby producing cost-saving of US33/DALY averted per 1000 live births. Further, an average of US.5 million would be required annually to achieve 100% coverage of HIV+ migrant women. Therefore, provision of ANC and PMTCT services to migrant women is cost-effective when compared to not offering PMTCT services and allows the government to avoid the long-term cost of antiretroviral therapy (ART) provision.