BACKGROUND: Routine immunization coverage has stagnated over the past decade and fallen short of WHO targets in Ethiopia. Community engagement strategies that reach beyond traditional health systems may reduce dropout and increase coverage. This evaluation assesses changes in immunization, postpartum family planning, and antenatal care coverage after implementation of an enhanced community engagement and defaulter tracing strategy, entitled "Fifth Child" project, across two districts in Benishangul-Gumuz Regional State (BGRS), Ethiopia. METHODS AND FINDINGS: A formative evaluation was conducted to examine the contribution of the strategy on immunization, postpartum family planning and antenatal care utilization in Assosa and Bambasi districts of BGRS. The quantitative findings are presented here. Routine and project-specific data were analyzed to assess changes in uptake of childhood vaccinations, postpartum family planning and antenatal care. Between January 2013 and December 2016, pentavalent-3 coverage increased from 63% to 84% in Assosa, and from 78% to 93% in Bambasi. Similarly, measles vaccine coverage increased from 77% to 81% in Assosa, and from 59% to 86% in Bambasi. Approximately 54% of all eligible infants across both woredas defaulted on scheduled vaccinations at least once during the period. Among defaulting children, 84% were identified and subsequently caught up on the vaccinations missed. Secondary outcomes of postpartum family planning and antenatal care also increased in both woredas. CONCLUSION: The "Fifth Child" project likely contributed to enhanced immunization performance and increased utilization of immunization and select perinatal health services in two woredas of BGRS. Further research is required in order to determine the impact of this community engagement strategy.