Objective: To compare the efficacy of a single-dose regimen with two-dose regimen of intravenous ceftriaxone as antibiotic prophylaxis for caesarean section. Design: Randomized controlled trial. Setting: Department of Obstetrics and Gynaecology, Federal Medical Centre, Abeokuta. Population: Pregnant women undergoing caesarean section that met the study inclusion criteria. Method: One hundred and four women who consented to the study were randomly assigned to receive intravenous ceftriaxone either as a single-dose regimen or as a twodose regimen for antibiotic prophylaxis at caesarean section. Maternal bio-data and infectious morbidity outcome were compared between the two groups. Main outcome measure: Incidence of post-caesarean section morbidity, postpartum fever, postpartum endometritis, wound infection and urinary tract infection.