The transversus abdominis plane (TAP) block is an effective method of providing postoperative analgesia in patients undergoing midline abdominal wall incisions. We evaluated its analgesic efficacy over the first 48 postoperative hours after cesarean delivery performed through a Pfannensteil incision, in a randomized controlled, double-blind, clinical trial. Fifty women undergoing elective cesarean delivery were randomized to undergo TAP block with ropivacaine (n = 25) versus placebo (n = 25), in addition to standard postoperative analgesia comprising patient-controlled IV morphine analgesia and regular diclofenac and acetaminophen. All patients received a standard spinal anesthetic, and at the end of surgery, a bilateral TAP block was performed using 1.5 mg/kg ropivacaine (to a maximal dose of 150 mg) or saline on each side. Each patient was assessed postoperatively by a blinded investigator: in the postanesthesia care unit and at 2, 4, 6, 12, 24, 36, and 48 h postoperatively. The TAP block with ropivacaine compared with placebo reduced postoperative visual analog scale pain scores. Mean (+/- sd) total morphine requirements in the first 48 postoperative hours were also reduced (66 +/- 26 vs 18 +/- 14 mg, P < 0.001), as was the 12-h interval morphine consumption up to 36 h postoperatively. The incidence of sedation was reduced in patients undergoing TAP blockade. There were no complications attributable to the TAP block. The TAP block, as a component of a multimodal analgesic regimen, provided superior analgesia when compared with placebo block up to 48 postoperative hours after elective cesarean delivery.