Background: Globally, the gestational diabetes mellitus prevalence is increasing. However, it isrnan overlooked health problem that highly endangers both women and their children in countriesrnof resource-constrained. Little is known about its burden in Ethiopia, particularly there is nornstudy on gestational diabetes in the area of present study. rn Objective: To assess the Prevalence of gestational diabetes mellitus and associated factorsrnamong pregnant mothers following antenatal care at public health facilities in Bule Hora town,rnOromia, Southern Ethiopia, 2021. rnMethods: A health facilities based cross-sectional study was conducted from February to April,rn2021. 190 pregnant mothers at 24-32 weeks of gestational age were selected by the convenientrnsampling technique. Measurement of fasting blood glucose level was performed to diagnoserngestational diabetes mellitus. Gestational diabetes mellitus was diagnosed using updated 2013rnWorld Health Organization diagnostic criteria. Analyses of bivariate and multivariate were donernby using SPSS version 25.0 to recognize factors linked with gestational diabetes mellitus. rnResults: The overall prevalence of gestational diabetes mellitus was found to be 7.4%. Familyrnhistory of diabetes mellitus (AOR = 5.7; 95% CI: 1.28-25.27), Triglycerides (AOR =5.6; 95%rnCI: 1.258-25.46), History of having macrocosmic baby (AOR =6.8; 95% CI: 1.56-29.59) andrnHistory of abortion (AOR = 4.4; 95% CI: 1.09-18.39) were found to be significantly associatedrnwith gestational diabetes mellitus. rnConclusion: The overall prevalence of gestational diabetes mellitus was 7.4%. History ofrnabortion, History of having macrocosmic baby, Family history of diabetes and elevated serumrntriglycerides were independently linked with gestational diabetes mellitus. Universal screeningrnand early diagnosis of gestational diabetes mellitus are strongly recommended.