This single-centre, randomised controlled trial compared the use of chlorhexidine-alcohol and iodine-alochol for preoperative skin antisepsis for prevention of surgical-site infection after cesarean delivery. 572 patients were assigned to chlorhxidine-alcohol and 575 to iodine-alcohol. Surgical-site infection was diagnosed in 23 patients (4%) in the chlorhexidine-alcohol group and 42 (7.3%) in the iodine-alcohol group (RR 0.55, 95% CI 0.34–0.90; p=0.02). These results are consistent with those of prior studies that suggest the superiority of chlorhexidine-based antiseptics over iodine-based antiseptics for the prevention of surgical-site infection. Although these previous studies suggested the superiority of chlorhexidine-based antiseptics, it remained unclear whether the superiority was attributable to the chlorhexidine, the alcohol, or the combination and whether these results would apply to cesarean delivery.