Between 1980 and 1992, 908 patients underwent single aortic (n = 178), single mitral (n = 577), or double aortic and mitral (n = 153) valve replacement with the St. Jude Medical valve at our hospital. There were 392 male patients and 516 female patients whose ages ranged from 1.2 to 74 years (mean, 52 years). The early mortality rate was 5.0% (45 patients). A 94% complete follow-up was accomplished for 863 patients who were discharged from the hospital (4682.3 patient-years). Sixty-nine of these patients died, for a late mortality rate of 8.0%. Fifty-two patients, including four patients (0.3%/100 patient-years) had anticoagulant-related hemorrhage, 4(0.1%/100 patient-years) had prosthetic valve endocarditis, 11 (0.2%/100 patient-years) had nonstructural valve dysfunction, and 16 (0.3%/100 patient-years) underwent reoperation. There were no structural valve failures in this series. The total number of valve-related deaths was 22. Of those patients who survived, 98% were in New York Heart Association functional class I or II at the date of the last follow-up. The probabilities of freedom from thromboembolism and anticoagulant-related hemorrhage at 10 years were 94% +/- 2% and 97% +/- 2% in aortic valve replacement, 89% +/- 2% and 98% +/- 4% in mitral valve replacement, and 89% +/- 6% and 92% +/- 6% in double valve replacement, respectively. Significant hemolysis related to the St. Jude Medical valve occurred in 8 of the 577 patients who received mitral valve replacement in our early experience, and modifying the valve orientation appeared to play an important role in reducing hemolysis. The event-free rate, including all complications and late deaths, at 10 years was 75% +/- 7%, 74% +/- 3%, and 81% +/- 6% in aortic valve replacement, mitral valve replacement, and double valve replacement, respectively. On the basis of these results, the St. Jude Medical valve seems to be an excellent mechanical valve in terms of durability and low thrombogenicity and remains our prosthetic valve of choice when valve replacement with a mechanical valve is indicated.