To determine the clinical and echocardiographic outcome of left ventricular hypertrophy a prospective study was undertaken of 104 nondiabetic dialysis patients without dilated cardiomyopathy, who were followed for 3-5 years. 33% of patients had normal echocardiogram, 41% mild and 27% severe hypertrophy (left ventricular wall thickness greater than or equal to 1.4 cm in diastole). In the first 2 groups 16% progressed to severe hypertrophy, 23% were admitted with congestive heart failure after starting dialysis therapy, and 2-year cumulative survivals were 97 and 85%. In the group with severe hypertrophy 88% already had severe hypertrophy on starting dialysis therapy, it was persistent in 87%, 50% were admitted at least once with congestive heart failure, and the 2-year cumulative survival was 53%. 71% of those who died in the severe group died from cardiac or cerebrovascular causes compared to none of those with normal echocardiogram, which accounted for the significantly worse (p = 0.001) survival. We conclude that severe left ventricular hypertrophy occurs frequently in dialysis patients, is often present at the start of end-stage renal disease therapy, is persistent, may predispose to congestive heart failure, and is associated with a high mortality.