Facility-based delivery service is recognized as intermediation to reduce complications during delivery. Current struggles to reduce maternal mortality in low-and-middle income countries, including Ethiopia, primarily focus on deploying skilled birth attendants and upgrading emergency obstetric care services. This study was designed to assess utilization of health facility–based delivery service and associated factors among mothers who gave birth in the past 2 years in Gindhir District, Southeast Ethiopia. A community-based cross-sectional study design was conducted in Gindhir District from March 1 to 30, 2020, among 736 randomly selected mothers who gave birth in the past 2 years. A multistage sampling technique was used to select the study participants and a pretested, structured questionnaire was used to collect data through face-to-face interviews. The collected data were managed and analyzed using SPSS version 23. Of the 736 mothers interviewed, 609 (82.7%), 95% CI: 80.1, 85.5%, of them used health facilities to give birth in the past 2 years for their last delivery. Mothers who lived in rural areas had 4 or more ANC visits, received 3 or more doses of the TT vaccine, and had good knowledge of maternal health services were found to have a statistically significant association with facility-based delivery service utilization. In Gindhir District, mothers have been using health facility–based delivery services at a high rate for the past 2 years. Higher ANC visits and TT vaccine doses, as well as knowledge of maternal health services and being a rural resident, were all linked to using health facility–based delivery services. As a result, unrestricted assistance must be provided to mothers who have had fewer ANC visits and have poor knowledge on maternal health services.