Background Hepatitis B virus (HBV) infection is a serious public health problem in sub-Saharan Africa pregnant women. HBV Infection has high tendency of vertical transmission and have adverse effect on both the mother and child. However, there is no evidence on prevalence of hepatitis B virus among pregnant women in Wolaita Zone. Therefore, this study aims to determine prevalence and associated factors of hepatitis B virus infection among pregnant attending Antenatal clinics of public Hospitals of Wolaita Zone. Method An institution based cross sectional study was conducted among pregnant women attending antenatal clinics of Wolaita Zone from October-November, 2018. Systematic random sampling was used to get respondents. A pretested, structured questionnaire was used to collect socio-demographic characteristics and other variables. In addition, 5 ml of venous blood was collected from each study participants and serum was tested for Hepatitis B surface antigen. Data was entered to Epidata 3.1 version and exported Statistical Package for Social Sciences Version 20.0 for descriptive and logistic regression analysis. All variables in bivariate analysis with p<0.25 were taken to multivariable analysis. P-value and Odds ratio with 95% CI was used to measure the presence and strength of the association respectively. Result The prevalence of Hepatitis B surface Antigen among pregnant women was 49(7.3%). History of multiple sexual partners (