BackgroundImproving newborn survival is essential if Ethiopia is to achieve Millennium Development Goal 4. The national Health Extension Program (HEP) includes community-based newborn survival interventions. We report the effect of these interventions on changes in maternal and newborn health care practices between 2008 and 2010 in 101 districts, comprising 11.6 million people, or 16% of Ethiopia’s population.Methods and FindingsUsing data from cross-sectional surveys in December 2008 and December 2010 from a representative sample of 117 communities (kebeles), we estimated the prevalence of maternal and newborn care practices, and a program intensity score in each community. Women with children aged 0 to 11 months reported care practices for their most recent pregnancy and childbirth. The program intensity score ranged between zero and ten and was derived from four outreach activities of the HEP front-line health workers. Dose-response relationships between changes in program intensity and the changes in maternal and newborn health were investigated using regression methods, controlling for secular trend, respondents’ background characteristics, and community-level factors.Between 2008 and 2010, median program intensity score increased 2.4-fold. For every unit increase in the score, the odds of receiving antenatal care increased by 1.13 times (95% CI 1.03–1.23); the odds of birth preparedness increased by 1.31 times (1.19–1.44); the odds of receiving postnatal care increased by 1.60 times (1.34–1.91); and the odds of initiating breastfeeding immediately after birth increased by 1.10 times (1.02–1.20). Program intensity score was not associated with skilled deliveries, nor with some of the other newborn health care indicators.ConclusionsThe results of our analysis suggest that Ethiopia’s HEP platform has improved maternal and newborn health care practices at scale. However, implementation research will be required to address the maternal and newborn care practices that were not influenced by the HEP outreach activities.