Because the impact of diuretic use on mortality in acute congestive heart failure (CHF) is not known, we examined the association between drug use, fluid balance, and death among 1,150 patients hospitalized for evaluation and treatment of CHF. After adjusting for other relevant intergroup differences, we observed that less net weight loss and a greater number of intravenous drug doses retained significant predictive value for death, suggesting that more frequent diuretic dosing or diuretic resistance may be related to mortality in acute CHF.