The CM prosthesis was implanted in 1,258 patients (709 males, 549 females; mean age 60.9 ± 12.3 years) between 1989 and 1997. Aortic valve replacement (AVR) was performed in 613 patients, mitral valve replacement (MVR) in 447, and multiple replacement (MR) in 231. Risk factors assessed were age or age groups, gender, CAB, previous surgery, rhythm, valve position, status and NYHA functional class. Total follow up was 4,765.0 patient-years (pt-yr), and 98.4% complete. The overall early mortality rate was 5.6%; late mortality rate was 3.7%/pt-yr; valve-related mortality rate was 1.1%/pt-yr. The total thromboembolism (TE) rate was 4.1%/pt-yr; the major TE rate was 1.9%/pt-yr and fatal TE rate 0.31%/pt-yr. The valve thrombosis rate was 0.31%/pt-yr; fatal thrombosis rate was 0.06%/pt-yr. The hemorrhage rate was 2.7%/pt-yr; fatal hemorrhage rate was 0.4%/pt-yr. The reoperation rate was 1.0%/pt-yr; fatal 0.1%/pt-yr. Actuarial freedom from TE at eight years was 77.3 ± 2.8%; major TE 88.5 ± 1.6%, and hemorrhage 76.4 ± 3.2%. The only predictor for TE major was status (emergency > urgent > elective). Actuarial freedom from valve-related mortality at eight years was 91.4 ± 1.8%, and from valve-related reoperation 91.1 ± 2.4%. Overall survival rate at eight years was 68.2 ± 2.3%. In conclusion, the clinical performance of the CarboMedics mechanical prosthesis is satisfactory when implanted in the mitral, aortic and multiple positions.