Conventional microsurgical reanastomosis was compared with laser microsurgical reanastomosis of the ligated uterine horn in the rabbit. Fourteen virgin female New Zealand white rabbits had both uterine horns ligated and divided at laparotomy. Four weeks later, 7 rabbits had conventional microsurgical reanastomosis of the divided uterine horns after the ligated stumps were excised. The ligated uterine horns of the other 7 animals were incised with a CO2 laser with a power density of 637-796 W/cm2 followed by conventional microsurgical reanastomosis using polyglactin (Vicryl) 8-0 sutures. After 6 wk, a laparotomy was performed to determine adhesion formation and uterine horn patency by chromoperturbation. Adhesion formation was graded 0 (no adhesions) through 3 (extensive, dense adhesions) for each uterine horn. Only 1 uterine horn in the control group was not patent. Only 1 uterine horn in the control group was not patent. Laser microsurgery produced significantly less adhesion (mean .+-. SE, 0.79 .+-. 0.24) than conventional microsurgery (2.29 .+-. 0.13) (P < 0.001). Laser microsurgical tubal reanastomosis evidently produces significantly better results with less adhesion than the conventional microsurgical technique.