The annual mortality rate among patients receiving long-term hemodialysis has been rising over the past decade. The prevalences of known risk factors such as older age, male sex, duration of dialysis, presence of diabetes, coronary artery disease, or hypertension do not seem to have changed during this time. However, evidence suggests that an increased body aluminum level may have an adverse effect on survival even in the absence of overt aluminum toxic reaction. Therefore, we evaluated the correlation between serum aluminum levels and mortality in 10 646 patients undergoing long-term hemodialysis. Mortalities were 18% higher for patients with serum aluminum levels between 1520 and 2220 nmol/L and progressively increased to 60% higher for patients with aluminum levels above 7410 nmol/L. Serum aluminum level was an important predictor of survival even after other known risk factors had been controlled. These data strongly suggest that patients undergoing long-term hemodialysis should have periodic surveillance of the serum aluminum levels, and in those patients who have plasma levels of 1520 to 2220 nmol/L or higher, one should seriously consider discontinuing aluminum salts and giving therapy to decrease body aluminum level if it is found to be increased.