Two hundred and fifty apparently healthy pregnant women attending the Obstetrics and Gynecology Clinic of the Lagos University Teaching Hospital (LUTH), Lagos, Nigeria were screened for a comparison of the prevalence of HIV seropositivity and hepatitis B surface antigenemia (HBs Ag) amongst them. The Karpas AIDS cell test for HIV seropositivity and Bioman Hepatitis test kits were used as described by the manufacturers. HIV seropositive cases were confirmed using the Western blot test. Results revealed that out of the 250 pregnant women screened, 2 (0.8%) and 11 (4.4%) were HIV-1 and HBs Ag seropositive, respectively. However, the same 2 pregnant women now constituting 2 (18.2%) of the 11 HBs Ag positive pregnant women were simultaneously HIV-1 seropositive. Antibody to HIV-2 was not recorded in all HIV seropositive cases. This is the first report on the simultaneous prevalence of HBs Ag and HIV seropositivity among apparently healthy pregnant women in Lagos, Nigeria.