Only limited data of the long-term effect of levosimendan on renal dysfunction in patients with decompensated heart failure (DHF) have been published previously. To date, there has been no similar study carried out in a Chinese population. A prospective, randomized, placebo-controlled, and double-blind study was performed to investigate the effect of levosimendan on estimated glomerular filtration rate (eGFR) in DHF patients with renal dysfunction during a 30-day period. Sixty-six patients with left ventricular ejection fraction (LVEF) ≤40% and eGFR 15-89 mL/min/1.73 m(2) were randomized in a 1:1 ratio to receive a 24-h infusion with levosimendan or placebo. The B-type natriuretic peptide (BNP) and eGFR were determined at baseline and day 1, 3, 7, 14, 30 after the start of treatment. The eGFR levels were obviously enhanced following levosimendan, peaked at 3 days, sustained for at least 14 days, and returned to baseline by day 30 after starting infusion. In contrast, placebo did not induce any significant changes in eGFR levels during the follow-up. In addition, levosimendan resulted in a distinct decrease in BNP levels in comparison with placebo, and the beneficial effect returned to baseline by day 14 and remained so at day 30 postinfusion. A 24-h infusion with levosimendan transiently improved the renal dysfunction compared with placebo in patients with DHF, and its beneficial effects persisted for at least 14 days after the initiation of treatment.