An elevated blood urea nitrogen (BUN) in known to be an important prognostic indicator in patients with end-stage heart or kidney disease or certain other life-threatening illnesses. However, it is less certain as to whether an elevated BUN is an independent predictor of long-term mortality risk in less seriously ill patients. To address this issue, we examined the relationship between BUN and long-term mortality after adjusting for potential confounders and other indicators of health status/disease severity, in a select population of older medically stable Veterans.