The purpose of the study reported here was to determine whether dogs with chronic valvular disease have increased plasma C-reactive protein concentration, compared with that in clinically normal dogs. Blood was collected from 47 dogs with physical and echocardiographic evidence of chronic valvular disease and from 20 healthy controls. C-reactive protein concentration was determined with a commercial canine C-reactive protein enzyme immunoassay. Compared with controls, dogs with chronic valvular disease had higher plasma concentration of C-reactive protein (median 2.17 μg/mL [range, 0.86-33.8 μg/mL]) versus 1.43 μg/mL [range, 0.84-4.99 μg/mL]; P <.001). C-reactive protein concentration was not related to the presence of congestive heart failure or murmur grade. The results of this study suggest that increased concentration of C-reactive protein is found in dogs with chronic valvular disease.