INTRODUCTION: Prevention of mother-to-child transmission (PMTCT) remains a cornerstone of HIV prevention and control efforts. It is vital that the beneficiaries of PMTCT programs understand PMTCT recommendations, especially since their adherence to recommendations is key to successful PMTCT. There have been several major changes in PMTCT recommendations, and many women have encountered different recommendations. It is plausible that confusion has arisen as to what is currently recommended for successful PMTCT. This confusion can affect adherence to recommendations and hinder PMTCT efforts. However, little is known about how women enrolled in PMTCT understand the recommendations in the context of these frequent changes. AIM: In this paper, we present our findings regarding how HIV-positive women enrolled in PMTCT in Kilimanjaro understand PMTCT recommendations pertinent to them. METHODS: From August 2019 to April 2020, we surveyed 521 mothers enrolled in PMTCT in seven districts in the Kilimanjaro region, Northern Tanzania. A pretested questionnaire was administered to consenting mothers. The questionnaire collected information on mothers' demographic characteristics, previous encounters with PMTCT, and knowledge of various PMTCT program elements, including medication duration, breastfeeding recommendations and infant HIV testing schedule. A logistic regression model was used to determine factors associated with good PMTCT knowledge among mothers. RESULTS: A total of 521 women were enrolled, the median score for the 19 items used to assess knowledge was 57.9%, and 64.9% scored above the median. Counselling on ART (OR=2.17, 95% CI 1.08-4.36) and counselling on breastfeeding during the ANC visits (OR=2.38, 95% CI 1.38-4.11) were the only factors that we found to be significantly associated with higher odds of good knowledge of PMTCT. CONCLUSION: Even amongst mothers enrolled in PMTCT, poor understanding regarding key PMTCT recommendations prevails. There is a need to reassess the training modalities and look at ways to reinforce PMTCT messages to mothers.