Hepatitis B virus (HBV) infection is endemic in sub-Saharan Africa, Nigeria inclusive, and it is common among HIV/AIDS patients. The aim of this study is to determine the prevalence of hepatitis B virus serological markers and associated risk factors among HIV-positive female patients on HAART in Ogun State, Nigeria. After receiving ethical permission from the Babcock University Health Research Ethics Committee (BUHREC), 100 female HIV-infected patients from Babcock University Teaching Hospital (BUTH), Ilishan-Remo, Ogun State, and General Hospital, Ijebu-Ode, Ogun State, were recruited for the study. The patients' HIV status was confirmed using three rapid diagnostic kits, all of which were used according to the manufacturer's instructions: Determine (Abbott Laboratories, Tokyo, Japan), Unigold HIV (Trinity Biotech Plc Bray, Co. Wicklow, Ireland), and 1/2 Stat Pak (Abbott Laboratories, Tokyo, Japan) (Chembio Diagnostic Systems, New York, USA). While an HBV 5-in-1 Panel supplied by Innovation Biotechnology Co., Ltd, Beijing, China was used for the qualitative detection of HBV markers in serum specimens. Out of the 100 study participants examined, 4(3.6%) were positive for HBsAg, 2 (1.8%) were positive for HBsAb, 81 (73.6%) were positive for HBeAg, 3 (2.7%) were positive for HBeAb, while 65 (59.1%) were positive for HBcAb. There was no significant association between the occurrences of HBsAg and HBsAb and the socio-demographic characteristics of the study participants (P>0.05), except for HBeAg and HBeAb (P<0.05). Identified risk factors include: lack of knowledge of HBV, lack of a history of HBV vaccination, history of blood transfusion, organ transplant, and unprotected sex among others. The findings demonstrate that Hepatitis B Virus (HBV) infection exists among HIV-positive female patients on HAART in Ogun State, Nigeria, particularly among the age categories of 18-25 years and 26-30 years. This necessitates ongoing and persistent public health interventions among the study population.