BACKGROUND Bacterial vaginosis presents with malodorous vaginal discharge and is a potential cause of adverse reproductive and neonatal outcomes with a greater preponderance in the black race. Despite advancement in molecular technology, its aetiology, pathology and effective treatment remains unknown. Identification of its prevalence and its predisposing factors is necessary for its prevention. AIM The study aims at determining the prevalence of bacterial vaginosis among pregnant women at booking and factors associated with bacterial vaginosis at maternity units of Lagos State University Teaching Hospital, Ikeja. METHODOLOGY The study carried out was a prospective cross-sectional study which was carried out at the maternity units of the Department of Obstetrics and Gynaecology, Lagos State University Teaching Hospital situated at Isolo and IfakoIjaye. It involved 350 consenting participants who were randomly and serially recruited until an adequate sample size was attained. Structured interview-based questionnaires were administered to all eligible selected participants. Smears were made from high vaginal swab taken aseptically, gram-stained and examined under the microscope for features of bacterial vaginosis using the Nugent scoring system. Data obtained were analysed using Epi-info 3.5.1.