Background: The clinical significance of urinary liver fatty acid-binding protein (u-LFABP) in acute heart failure (AHF) patients remains unclear. Methods and Results: The u-LFABP levels on admission of 293 AHF patients were analyzed. The patients were divided into 2 groups according to the u-LFABP quartiles (Q1, Q2, and Q3 = low u-LFABP [L] group vs. Q4 = high u-LFABP [H] group). We evaluated the diagnostic and prognostic value of u-LFABP and compared the findings between the chronic kidney disease (CKD; n = 165) and non-CKD patients (n = 128). Acute kidney injury (AKI) during the first 7 days was evaluated based on the RIFLE criteria. In the non-CKD group, the number of AKI patients during the first 7 days was significantly greater in the H group (70.0%) than in the L group (45.6%). A multivariate logistic regression model indicated that the H group (odds ratio: 3.850, 95% confidence interval [CI] 1.128-13.140) was independently associated with AKI during the first 7 days. The sensitivity and specificity of u-LFABP for predicting AKI were 63.6 and 59.7% (area under the ROC curve 0.631) at 41.9 ng/mg × cre. A Cox regression model identified the H group (hazard ratio: 13.494, 95% CI 1.512-120.415) as an independent predictor of the 60-day mortality. A Kaplan-Meier curve, including all-cause death within 60 days, showed a significantly poorer survival rate in the H group than in the L group (p = 0.036). Conclusions: The u-LFABP level is an effective biomarker for predicting AKI during the first 7 days of hospitalization and an adverse outcome in AHF patients with non-CKD.