BACKGROUND: Universal antiretroviral therapy (ART) for all pregnant/ breastfeeding women living with Human Immunodeficiency Virus (HIV), known as Prevention of mother-to child transmission of HIV (PMTCT) Option B+ (PMTCTB+), is being scaled up in most countries in Sub-Saharan Africa. In the transition to PMTCTB+, many countries face challenges with proper implementation of the HIV care cascade. We aimed to describe the feasibility of a PMTCTB+ approach in the public health sector in Swaziland. METHODS: Lifelong ART was offered to a cohort of HIV+ pregnant women aged ≥16 years at the first antenatal care (ANC1) visit in 9 public sector facilities, between 01/2013 and 06/2014. The study enrolment period was divided into 3 phases (early: 01-06/2013, mid: 07-12/2013 and late: 01-06/2014) to account for temporal trends. Kaplan-Meier estimates and Cox proportional-hazards regression models were applied for ART initiation and attrition analyses. RESULTS: Of 665 HIV+ pregnant women, 496 (74.6%) initiated ART. ART initiation increased in later study enrolment phases (mid: aHR: 1.41; later: aHR: 2.36), and decreased at CD4 ≥ 500 (aHR: 0.69). 52.9% were retained in care at 24 months. Attrition was associated with ANC1 in the third trimester (aHR: 2.37), attending a secondary care facility (aHR: 1.98) and ART initiation during later enrolment phases (mid aHR: 1.48; late aHR: 1.67). Of 373 women eligible, 67.3% received a first VL. 223/251 (88.8%) were virologically suppressed (< 1000 copies/mL). Of 670 infants, 53.6% received an EID test, 320/359 had a test result recorded and of whom 7 (2.2%) were HIV+. CONCLUSIONS: PMTCTB+ was found to be feasible in this setting, with high rates of maternal viral suppression and low transmission to the infant. High treatment attrition, poor follow-up of mother-baby pairs and under-utilisation of VL and EID testing are important programmatic challenges.