The transanal approach is a relatively new technique for surgery of Hirschsprung's disease. The purpose of this experimental study was to evaluate and compare the transanal endorectal pull-through when it takes place with laparoscopic assistance, according to Soave-Georgeson procedure and without laparoscopic assistance. We used two separated groups of animals. In the 1st group the transanal endorectal pull-through was performed by retrograde transanal mucosectomy with laparoscopic devascularization of the colon and in the 2nd group the transanal endorectal pull-through was performed without laparoscopic assistance. In the 1st group the transitional zone of the colon was determined laparoscopically while in the 2nd group during the perineal devascularization of the bowel. In both groups end to end coloanal anastomosis was performed in the same way. The postoperative course was uneventful, no severe long-term problems were observed. Four months after operation the experimental subjects of the 1st group had 3-4 discharges in 24 hours. While the experimental subjects of the 2nd group had 5-7 discharges in 24 hours. Manometric resting anal sphincters pressure in the 1st group averaged 77 +/- 16 mmHg compared with 74 +/- 15 mmHg in the 2nd group. The transanal colectomy technically can be performed with or without laparoscopic assistance. However the advantages of laparoscopic assistance are the following: 1) more exact determination of transitional zone; 2) easier separation of peritoneal reflection, 3) better control of final position of the colon; 4) minor retraction on the perineal muscles.