We conducted a programmatic, observational cohort study with mother-infant pairs (MIPs) enrolled in prevention-of-mother-to-child-transmission (PMTCT) programs in Malawi to assess the feasibility and potential HIV-related benefits of integrating Early Childhood Development (ECD) services into PMTCT programs. Six health facilities were included in the intervention. We offered ECD counseling from the WHO/UNICEF Care for Child Development package in PMTCT waiting spaces while MIPs waited for PMTCT and broader treatment consultations. Primary outcomes were mothers' retention in HIV care at 12 months and infant HIV testing at 6 weeks and 12 months after birth. Routine facility-level data from six comparison health facilities were collected as an adhoc standard of care comparison and used to calculate the cost of delivering the intervention. A total of 607 MIPs were enrolled in the integrated ECD-PMTCT intervention between June 2018 and December 2019. The average age of MIPs was 30 years and 7 weeks respectively. We found that 86% of mothers attended ≥ 5 of the 8 ECD sessions over the course of 12 months; 88% of intervention mothers were retained in PMTCT versus 59% of mothers in comparison health facilities, and 96% of intervention infants were tested for HIV by six weeks compared to 66% of infants in comparison health facilities. Costing data demonstrated the financial feasibility of integrating ECD and PMTCT programs in government health facilities in Malawi. Integrating ECD into PMTCT programs was feasible, acceptable, resulted in better programmatic outcomes for both mothers and infants. Further investigation is required to determine optimal delivery design for scale-up.