We examined the prognostic significance of left ventricular hypertrophy determined by echocardiography in a cohort beginning renal replacement therapy. No patient had hemodynamically significant valvular disease or echocardiographic signs of obstructive cardiomyopathy. Using the Cox proportional hazards model, left ventricular hypertrophy was significantly associated with survival. The relative risk, based on comparison of upper and lower quintiles of left ventricular mass index, was 3.7 (95% confidence intervals, 1.6 to 8.3) for all-cause mortality and 3.7 (95% confidence intervals, 1.2 to 11.1) for cardiac mortality. The independent risk, adjusted for age, known coronary artery disease, diabetes, level of systolic blood pressure, and treatment (dialysis or transplantation), was 2.9 (95% confidence intervals, 1.3 to 6.9) for all-cause mortality and 2.7 (95% confidence intervals, 0.9 to 8.2) for cardiac mortality. Therefore, left ventricular hypertrophy appears to be an important, independent, determinant of survival in patients receiving therapy for end-stage renal failure.