From December 1970 to June 1978, 833 patients were operated upon for isolated mitral valve replacement (MVR: n = 361), isolated aortic valve replacement (AVR: n = 345), and aortic plus mitral valve replacement (DVR: n = 127) by the use of the Björk-Shiley tilting disc valve. Operative mortality for the entire series was 15 %. A comparison of operative deaths and numbers of patients treated each year shows considerable improvement in overall operative mortality. The 5 year survival rate (including operative mortality) calculated by the actuarial method was 81.4 % for MVR, 73.1 % for AVR, and 66.8 % for DVR. The 5 year survival rate of operative survivors was 94.9 % for MVR, 85 % for AVR, and 83.2 % for DVR. The 5 year complication free survival rate (death/removal/embolus free survival rate) including operative mortality was 69.7 % for MVR, 71.8 % for AVR, and 62.8 % for DVR. The postoperative hemodynamic result was evaluated in 58 consecutive patients with AVR and DVR. Enddiastolic volume fell after operation from 161 to 104 ml/m2 in AVR and from 156 to 103 ml/m2 in DVR. Ejection fraction increased from 54 to 65 % in AVR and from 50 to 61 % in DVR. Physical working capacity improved after operation in about two-thirds of all patients. A comparison of the cumulative 5 year survival rate of operative survivors between the Björk-Shiley and other models of mechanical valves shows a superiority of the Björk-Shiley valve, especially in the mitral valve position (95 %). The quality of the Björk-Shiley valve is further substantiated by highest cumulative 5 year death/removal/embolus free survival rates (including operative mortality) when compared with other mechanical valve types. We conclude: