OBJECTIVE To compare the perioperative outcomes of single extrahepatic portosystemic shunt occlusion by complete and partial silk ligation and ameroid constrictor placement in dogs. DESIGN A retrospective analysis of 30 dogs with single congenital extrahepatic shunts. PROCEDURE Records between 1990 and 2000 were reviewed. Patient age, breed, weight, presenting clinical signs, clinical pathology results, diagnostic imaging results, the surgery procedure performed, implant used, time taken, intra operative complications and perioperative complications were recorded. Mortality rates were calculated. RESULTS Twenty dogs had a silk ligation procedure, 10 partially occluded and 10 completely. Ten dogs had an ameroid constrictor placement procedure. Ameroid constrictor surgery was significantly shorter in duration than silk ligation. Time for silk ligation was 91.8 +/- 35.2 minutes (median 90.0); time for ameroid constrictor placement was 71.5 +/- 12.0 (median 72.5, P = 0.049). A reduction in intraoperative complications was also noted in the ameroid constrictor surgery group. CONCLUSION The ameroid constrictor offered a surgical occlusion procedure of single extrahepatic portosystemic shunts in dogs that was clinically as effective as silk ligation in the perioperative period, with a significantly shorter surgery time.