Between January 1988 and December 1994, 4,097 patients underwent heart valve replacement at the Heart Center North Rhine-Westfalia, Bad Oeynhausen, 1,388 (33.8%) of them suffered from impaired left ventricular (LV) function. Overall hospital mortality was 2.3% (n = 95). In the poor LV function group it was 1.8% (n = 25). There was a significant increase of mortality from 1.5% in patients younger than 60 years to 4.9% in patients 80 years of age and older. Reoperations and emergency operations showed an additional increase of mortality each: 6.2% and 18.2%, respectively. Medium term survival (maximum 48 months) was assessed in a group of 2,006 patients operated between January 1991 and December 1993. The cumulative mortality for patients with poor LV function (n = 148) was 12.8%, whereas for those with normal LV function it was 6.1%. Our data suggest that left ventricular function is of minor importance as far as primary operative results are concerned. In long term follow up patients with valve replacement and poor LV function show an increased mortality mainly due to cardiac causes.