The objective of the present study was to evaluate the usefulness of the vertebral heart score (VHS) in coughing dogs with chronic degenerative mitral valve disease (MVD). Survey thoracic radiographs of 90 dogs with a history of cough and clinical and echocardiographic evidence of MVD were evaluated by 2 independent observers. The observers were asked to first determine the origin of the cough as cardiac, non-cardiac or mixed and then to measure the VHS. Agreement regarding diagnosis of the origin of cough was obtained (kappa=0.64) in 69 dogs. Of these 69 dogs, 28 (41%), 32 (46%) and 9 (13%) had a cough of cardiac, non-cardiac and mixed origin, respectively. The dogs with a cough of non-cardiac origin had a significantly lower VHS (mean +/- SD, 11 +/- 0.9) compared with those of dogs with a cough of cardiac or mixed origin (12.8 +/- 1 and 12.9 +/- 0.9, respectively). Receiver operating characteristic curve analysis showed that a VHS < or = 11.4 is fairly accurate for exclusion of a cough of cardiac origin in dogs with MVD. The results indicate that the VHS may be an additional tool for differentiating the origin of cough in dogs with MVD.