The cardiac vertebral size is arithmetic thorax radiography of relation between cardiac dimension and dorsal vertebras, quantifying the presence and cardiomegaly grade. This size has been made individual investigations resulting specific dates for different breeds and dates different for which one. Objective: determinate the vertebral heart size and the interobservational variability in healthy French poodle and with mitral valve chronic diseases. Methods: thirty sets of thoracic radiographs of French Poodle, were divided into two groups; (Normal) normal cardiopulmonary structures, and cardiomegaly with congestive heart failure. Cardiomegaly was confirmed by echocardiography to be caused by mitral regurgitation because of myxomatous mitral valve disease. Teen observers evaluated the radiographs; each patient was review an general exam, left thoracic radiography, electrocardiogram and echocardiography. Results were obtained for the French poodle breed which was 8,70v ± 0,4 for healthy dogs and 10,44 v ±0,5 for dogs with mitral chronic diseases. it was no differences between the observers Conclusion VHS of the normal French poodle were different between them and the other Buchanan publication and VHS method for heart size is independent of observer experience.