Aim: To compare histological and urodynamic outcome of the classical detrusorotomy with and without the aid of intravesical balloon distension. We also describe a new technique with multiple detrusor incisions instead of detrusorotomy. Methods: A total of 24 animals were included in the study. Three different techniques of autoaugmentation cystoplasty were applied to surgically reduced bladders of 14 sheep. Five sheep underwent surgical reduction of bladder capacity as control group and five sheep underwent sham operation. In Group DIB (detrusor incision with balloon), standard whole thickness incisions on bladder wall were performed and a silicon balloon was inflated intravesically postoperatively. Group DMB (detrusorotomy with balloon) and Group DM (detrusorotomy) underwent standard detrusorotomy. After measuring capacities and compliances, animals were sacrificed on 90th postoperative day. Bladders were histopathologically evaluated. Expression of vascular endothelial growth factor (VEGF), CD31, and microvessel density (MVD) was noted. Quantification of collagen subtypes was also performed. Results: The mean capacity and compliance for Group DM and control were not significantly different and both were lower than other augmentation groups and sham. In Groups DMB and DM fibrosis was significantly increased. The VEGF expression was lower in Group DIB with respect to other augmentation groups whereas MVD was not significantly different. Measurement of total collagen and collagen subtypes revealed an increase in total collagen of groups DMB and DM when compared to other groups. Quantification of collagen subtypes demonstrated that types I and III were significantly increased in aforementioned groups. Conclusion: Autoaugmentation omentocystoplasty in sheep model does not result in a reliable increase in bladder capacity and compliance. Intravesical balloon inflation makes the achievement more pronounced and significantly increases the bladder capacity and compliance. Neurourol. Urodynam. 30:1371-1375, 2011. (C) 2011 Wiley-Liss, Inc.