Objective: The objective of this study is to determine the sero-prevalence and associated factors of HBSAg among Pregnant Women attending antenatal care clinic in Jijiga town public Health facilities, Somali Regional State. Methods: Institution based cross-sectional study was conducted in the antenatal care clinics of Karmara Hospital and JIjiga Health Center from September26 to October 26/2013. Blood specimens were collected for detection of hepatitis B virus surface antigen from 222 pregnant women attending antenatal clinics of both health facilities. Bivarate and multivariate logistic regression analysis were employed and P-value less than 0.05 was considered as statistically significant. Results: A total of 4.5% of the pregnant women were reactive for HBsAg. Among the various factors affecting HBsAg sero-positivity, history of hospitalization and pregnant women that had dental procedure were found as independent predictors. Conclusion: The prevalence were intermediate endemicity and thus, routine screening of pregnant women for HBV infection and improving aseptic techniques in health facilities is needed.