Background: The risk of death from complications relating to pregnancy and childbirth over the course of women’s lifetime is higher in the developing countries. Increasing the health service of mothers and children through well-organized institutional delivery service is central to achieve reduced maternal and child mortality. Ethiopian government design deferent strategies to increase institutional delivery. However, it is not well understood about service utilization in the study area. Objective: To assess delivery service utilization and associated factors among mothers who gave birth in the last one year in Mandura district, Benshangul gumuze region, North West, Ethiopia, 2019. Methods: Community based cross-sectional study was conducted. By multi-stage sampling, sample was taken from three urban and six rural kebeles, total of 546 women who gave birth within the last one year preceding the study-using interviewer administered questionnaire. Bi-variable and multi-variable logistic regression models were used to determine factors associated. Odds ratios with 95% confidence interval was computed to measure the strength of association and statistical significance was declared at p-value <0.05 Results: Prevalence of institutional delivery was 38% CI (34%-42%). Factors significantly associated with institutional delivery were ANC visit (AOR= 1.80, 95%CI:1.12-2.91), knowledge on danger sign (AOR=3.60, 95%CI: 2.25-5.76), urban residency (AOR=2.09, 95%CI: 1.15-3.81), accessibility of health facility (AOR =4.6, 95% CI:2.01-10.89), husbands educational level, (primary (AOR=2.50, 95%CI: (1.27-4.91), secondary and above (AOR=2.36, 95%CI:1.24-4.48),maternal occupation (Gov-ernmental employee (AOR=2.05, 95%CI:1.00-4.18) and Private employer, (AOR=2.42, 95%CI:1.09-5.35). Conclusion and recommendation: prevalence of institutional delivery is low in mandura district as compere to national. ANC visit, favorable knowledge on danger signs, accessibility of health facility and level of education were significantly associated with institutional delivery. Strength to community based conversation and enhance the role of developmental army , improve in-formation regarding the danger signs of pregnancy and benefits of institutional delivery through avail-able communication networks, improve promoting antenatal care four standard visits for pregnant were recommended. Key words: Institutional delivery service, Factors, Mandura, Ethiopia, 20