Thirty patients were operated on with restorative proctocolectomy with an end-to-end ileal pouch-anal anastomosis constructed by double stapling (STP). Pouches were randomized to either J type or K type (folded by the principles used for the Kock continent ileostomy). Manovolumetric and functional results were compared. Patients were followed up for at least 6 months. K pouches acquired a significantly larger volume than the J-configurated pouches, and at 6 months the mean +/- SD volumes amounted to 361 +/- 59.8 ml versus 283 +/- 43.0 ml (p less than 0.01) with a concomitant reduction in 24-h frequency (4.4 +/- 1.5 versus 5.8 +/- 1.9; p less than 0.05). The initial postoperative mean reduction of resting anal pressure amounted to 33%. which was similar to that observed in a group of matched historical controls operated on with endoanal mucosectomy and hand-sutured pouch-anal anastomosis. Compared with these controls STP patients showed a superior overall functional result, most marked in the early postoperative period.