Objectives: to report the long term bile acid stimulation test results for dogs that have undergone complete suture ligation of a single congenital extrahepatic portosystemic shunt (EHCPSS) Methods: data were collected from the hospital records of all dogs that had undergone a complete suture ligation of an EHCPSS (in one or two procedures). Owners were invited to return to the referral centre or their local veterinarian. A control population of dogs diagnosed with idiopathic epilepsy undergoing bile acid stimulation tests were used for comparison. Results: Fifty-one study dogs were recruited. Mean ± SD follow up time was 62 ± 27.4 months. 48 dogs had no evidence of multiple acquired shunts (MAS) and a significant reduction in the pre and post-prandial serum bile acid (SBA) concentrations at long-term follow-up compared with pre-operatively, (p=<0.01 and p=<0.01 respectively). At long term follow-up in 64.7% and 86.3% of these dogs pre- and post-prandial SBAs were above the laboratory’s reference range. Pre- and post- prandial SBAs were statistically significantly greater for dogs that had undergone a full ligation (with no evidence of MAS) at all time points compared to the control dogs (p<0.001 for all comparisons). Clinical significance: SBAs do not normalise in the majority of dogs surgically corrected for their EHCPSS, remaining mildly increased. The results suggest that in dogs treated with complete suture ligation mild increases in SBAs are not clinically relevant if present in combination with no physical examination abnormalities, a normal body condition score and no relapse in clinical signs.