Background-Urine albumin excretion is an important predictor of adverse cardiovascular events in various populations. Its correlation in patients with acute heart failure has not been described. Methods and Results-This prospective, observational study included 115 patients presenting with acute heart failure. The urine albumin/creatinine ratio (UACR) was measured from spot urine samples collected on days 1 and 7 of hospitalization. Median UACR decreased from 83 to 22 mg/gCr on days 1 and 7, respectively (P<0.0001). The proportion of patients with normoalbuminuria (UACR <30 mg/gCr) increased from 31% on day 1 to 60% on day 7, whereas the proportion with microalbuminuria (UACR between 30 and 299 mg/gCr) and macroalbuminuria (UACR >= 300 mg/gCr) decreased, respectively, from 42% and 27% on day 1 to 30% and 10% on day 7 (P<0.0001). These changes in UACR were correlated with changes in serum bilirubin and N-terminal pro b-type natriuretic peptide concentrations (correlation coefficients 1.087 and 0.384, respectively; 95% confidence interval, 0.394-1.781 and 0.087-0.680, respectively; and P=0.003 and 0.013, respectively), although they were not correlated with change in estimated glomerular filtration rate. Conclusions-In this sample of patients presenting with acute heart failure, urine albumin excretion was often increased at admission to the hospital and decreased significantly within 7 days of treatment. The decrease was correlated with serum N-terminal pro b-type natriuretic peptide and bilirubin concentrations, although neither with baseline nor with changes in indices of renal function.