Abstract: Objective To assess the value of urinary liver-type fatty acid-binding protein (L-FABP) in early assessment of the severity of traumatic brain injury and in predicting the occurrence of acute kidney injury (AKI) following the brain injury. Methods Sixty-five patients with traumatic brain injury patients were divided into 4 groups according to their Glasgow coma scale (GCS) scores. Blood and urine samples were collected at 2, 6, 12, 24, 48 and 72 h after the injury to detect serum creatinine (SCr) level using biochemical analyzer and urinary L-FABP using enzyme-linked immunosorbent assay (ELISA), with samples from 15 healthy adults as controls. The correlations were analyzed among SCr, urinary L-FABP, GCS score upon admission and AKI occurrence. Results The patients with moderate to severe brain injuries showed significantly higher SCr and urinary L-FABP levels than the control group (P<0.05). GCS score of the patients was inversely correlated with the levels of SCr and urinary L-FABP (P<0.05), and the changes were more prominent in urinary L-FABP than in SCr. The incidence of AKI was 21.54% in these patients. In patients with AKI, urinary L-FABP reached the peak level as soon as 6 h after the injury, as compared with 24 to 48 h when peak SCr level occurred. Conclusion Urinary L-FABP can be used as a marker for early assessment of the severity of traumatic brain injury and for predicting the occurrence of AKI following the injury.