Seven hundred pregnant women referred for blood grouping were studied for the presence of some markers of Hepatitis B virus. After collection of personal data including place of permanent residence the sera were tested for the presence of HBs Ag and anti HBs. The sera positive for HBs Ag were tested for the "e" antigen and antibody. The results were analysed according to parity, age and geographical location. Six hundred and ninety-two results were available for analysis showing 464 (67.1%) to have antibodies. 215 (31.1%) had no marker whatsoever. 44 (6.4%) of the women were HBs Ag carriers. Eight of these had the e antigen indicating that 1.16 percent were therefore infective. Calculation was made to determine the extent of vertical transmission using the prevalence of the e antigen. 15% of HBV carrier rate in the population is due to perinatal transmission and this is significant. Parity, age and geographical location did not influence the prevalence of the various markers.