Blood and blood products are scarce in developing countries due to increasing demand and declining supply. Rational utilization of blood products is imperative and prompted this study, which identifies the risk factors for blood transfusion during C-sections in a tertiary hospital in Nigeria. This retrospective case-controlled study reviewed all C-sections in our hospital from January 1, 1998, to December 31, 2002. Clinical variables including demographic characteristics, surgical events, EBL, indication for transfusion, and the number of units transfused were recorded. A total of 1117 cesarean sections were performed within the study period. Sixty-three patients (5.6%) received blood transfusions. An unbooked patient was six times more likely to receive a blood transfusion during cesarean section than women who had had antenatal care (p<0.001). Grand-multiparous women were associated with intraoperative transfusion during cesarean section (p=0.004). Placental previa was significantly associated with transfusion during cesarean section (p=0.0002). Previous cesarean section was an associated factor for intraoperative transfusion at cesarean section (p=0.02). The factors associated with transfusion at cesarean section were lack of prenatal care, grand multiparity, previous cesarean section, and pregnancies complicated by placenta previa. These factors should be considered in the care of parturients for cesarean section, especially in developing countries.