It is not possible to diagnose acute kidney injury (AKI) in early stages with traditional biomarkers. Kidney injury molecule-1 (KIM-1) is a novel biomarker promising the diagnosis of AKI in early stages. We studied whether urinary and serum KIM-1 (KIM-1 U and KIM-1 S ) concentrations were useful in predicting cisplatin-induced AKI in early stages. We prospectively analysed 22 patients on cisplatin treatment. KIM-1 S and KIM-1 U concentrations were assessed in the samples of the patients on four different time periods (before treatment BT, first AT1, third AT3 and fifth AT5 day after treatment). KIM-1 U concentrations on the first day after cisplatin treatment in patients with AKI were significantly increased compared to both KIM-1 U concentrations of the same patients BT (P=0.009) and to AT1-KIM-1 U concentrations of the patients without AKI (P=0.008). A receiver operating characteristic analysis revealed that AT1-KIM-1 U concentrations may predict AKI with an 87.5% sensitivity and 93.3% specificity (area under the curve=0.94). KIM-1 S concentrations were not significantly changed between BT and AT periods. KIM-1 U concentrations may predict cisplatin-induced AKI in early stages with high sensitivity and specificity.