Secretin is a polypeptide hormone that stimulates secretion of bicarbonate from the exocrine pancreas and, in healthy human subjects, causes transient pancreatic duct dilation observable sonographically. In humans with chronic pancreatitis, secretin administration fails to cause pancreatic duct dilation, theoretically due to the restrictive effects of periductal fibrosis. We characterized the effect of exogenous secretin administration on the width of the pancreatic duct in nine healthy domestic cats. Cats were given a commercially available secretin product (ChiRho Stim™) while the pancreatic duct was monitored sonographically. Mean pancreatic duct diameter increased from 0.77±0.33 to 1.42±0.40 mm after secretin administration (P=0.0017). The mean percent increase in pancreatic duct diameter over basal diameter for all time points up to 15 min postsecretin administration was 101.9±58.8%. Applicability of this technique to diagnose chronic pancreatitis in cats will need to be investigated.