Adapter-modified Ussing chambers have been used for assessment of endoscopically obtained intestinal biopsies in humans. The aim of this study was to evaluate the feasibility of an adapter-modified Ussing chamber for assessment of intestinal transport physiology in endoscopically-obtained colonic biopsies from cats and dogs. Fifteen colonic biopsies from four cats and 13 colonic biopsies from four dogs were transferred into a modified Ussing chamber and sequentially exposed to several compounds. Baseline mean ± SD conductance was measured. Changes of short circuit current (Δ/sc) were observed after exposure to glucose (number of feline biopsies that responded = 0/number of canine biopsies that responded = 4), phloridzin ('n' = 0/'n' = 7), histamine ('n' = 5/'n' = 12), serotonin (n = 7/n = 12), prostaglandin (n = 5/n = 7), forskolin (n = 7/n = 7), and ouabain (n = 9/n = 7). The adapter-modified Ussing chamber studied here enables investigation of transport physiology of endoscopically-obtained colonic biopsies from companion animals. However, we observed a large variability of results, suggesting that clinical use of this method is limited.