To explore the use of the urinary neutrophil gelatinase associated lipocalin (uNGAL) in the early diagnosis of paraquat poisoning patients with acute kidney injury (AKI). Eighty five patients were from the emergency department in our hospital. Five ml blood and urine were collected from each patient at 15 min, 2, 4, 6, 8, 10, 12, 18, 24, 36, 48 and 72 h, 5 and 7d after admission. The uNGAL levels of urine were detected with ELISA test and the SCr levels were measured with creatine oxidase assay. Sixty two cases of paraquat intoxication suffered from AKI, the incidence was 72.94% (62/85). The SCr levels of 62 cases with AKI at 18, 24, 36, 48, 72 h and 5, 7 d after admission increased significantly, as compared with the baseline value and control group (P < 0.01). At 24, 36, 48, 72 h and 5, 7 d after admission, there was significant difference of the SCr levels between AKI group and non-AKI group (P < 0.01). At 2 h after admission, the uNGAL level of urine in paraquat intoxication AKI group was (96.21 +/- 45.32) microg/L which was significantly higher than the baseline value. At 10, 12, 18, 24, 36, 48, 72 h and 5, 7 d after admission, the uNGAL levels of urine in AKI group and non-AKI group obviously enhanced, as compared with the baseline value and control group (P < 0.01 or P < 0.05). At all time points, there was significant difference of the uNGAL level between AKI group and non-AKI group (P < 0.01). The uNGAL level of urine in paraquat intoxication patients at 2 h after admission significantly enhanced, which is earlier than enhanced SCr. So the uNGAL level of urine may serve as early diagnostic biomarker for AKI induced by paraquat intoxication.