Fourth grade a loud holodiastolic murmur was determined on the region from aortic valve with maximum intensity to cardiac apex in a 22 years-old Hannover horse determining aortic valve insufficiency which one of the most important pathologic valve problems in the horses. Phonocardiographic examinations were made in order to determine characteristic of murmur. It was determined that these phonocardiographic records included vibrations shows diastolic murmur and in this way it was produced that these recordings determined better the caharacter of cardiac murmur sounds and enabled to more reliable diagnosis.