The authors studied late results of replacement of the aortic valve by a ball prosthesis in 292 patients up to 11 years. Good results were obtained in 82.2% of the patients, satisfactory in 7.4%, unsatisfactory in 3%; 7.4% of patients died during late periods. The factors that deteriorate the late results of aortic valve prosthesis are the duration of subjective symptomatics over 5 years before the operation, the presence of the right ventricular decompensation, cardiomegaly, high end diastolic pressure in the left ventricle, neglected stage of the disease. These data are confirmed by the analysis of actual curves of survival and stability of the good late results of the operation.