This study was designed to evaluate the effect of maternity care by skilled providers on the occurrence of adverse pregnancy outcomes. A community-based cohort study was conducted at Dabat district, northwest Ethiopia, from December 1, 2011 to August 31, 2012. During the study period, 763 pregnant women were registered and followed until 42 days of their postpartum period. Use of skilled maternal care was the exposure variable. Reductions in occurrence of serious complications or death (adverse pregnancy outcomes) were used as outcome indicators. Data was collected at four time points; first contact, during the 9th month of pregnancy, within 1 week after delivery and at 42 days of postpartum. The effects of the exposure variable were evaluated by controlling potential confounders using logistic regression. One hundred and fifty-three (21 %) of the women encountered at least one obstetric complication or death during delivery and postpartum period. Hemorrhage and prolonged labor were the major types. Pregnancy outcomes for 41 women (5.6 %) were fetal, neonatal, or maternal deaths. Four or more ANC (antenatal care) visits, <4 ANC visits and delivery by skilled attendant showed 25 % (OR 0.75; 95 % CI 0.25, 2.75), 9 % (OR 0.91; 95 % CI 0.43, 1.69) and 31 % (OR 0.69; 95 % CI 0.36, 1.33) reduction in the occurrence of adverse pregnancy outcomes, respectively. Skilled maternal care showed reduction in adverse pregnancy outcomes (complications and deaths). However, the associations were not significant. Improving the quality of maternity care services and ensuring continuum of care in the health care system are imperative for effective maternal health care in the study area.