Abstract: Hepatitis B (HBV) is one of the commonest and wide spread infections of humans and it is most prevalent in developing countries, including Nigeria.The disease is closely related to HIV, with one influencing the other in no small measure. This study aims atdetermining the prevalence of hepatitis B surface antigen (HBsAg) among HIV positive patients attending Limi hospital in Central Area of Abuja. A total of 250 HIVpatients were screened for HBsAg, using rapid monochromatic test strip to determine the presence or absence of HBsAg in the samples. Of the 250 serum samples screened, 35 were positive for HBsAg, givingan overall prevalence of 14.0%.