Introduction: Acute hepatitis is acute inflammation of liver elicited by a large number of causes. It sometimes spontaneously recovers, sometimes may progress to chronic hepatitis. LiverFatty Acid Binding Protein (L-FABP) is a small protein that is abundant in hepatocytes, and which binds most of the longchain fatty acids present in the cytosol. Aim: The present study aimed to investigate the levels of serum and urine L-FABP in acute hepatitis and diagnostic value of serum and urine L-FABP levels in patients with acute hepatitis. Materials and Methods: The present study included a total of 85 patients. Total number of patients with acute hepatitis were 17 (five of acute hepatitis B, one of acute hepatitis A, two of acute hepatitis C, five of autoimmune hepatitis and four of toxic hepatitis), 19 of hepatic encephalopathy, 29 of liver cirrhosis, and 20 controls were included. Serum and urinary L-FABP levels were analyzed by the Enzyme-Linked Immunosorbent Assay (ELISA). Results: Serum L-FABP levels were 9110 +/- 3352.5, 9410 +/- 1355, 9715 +/- 2462 and 3672 +/- 982.5 ng/l in patients with acute hepatitis, hepatic encephalopathy and cirrhosis and control subjects, respectively. There were statistically significant positive correlations between serum levels of L-FABP and Aspartate Aminotransferases (AST), Alanine Aminotransferases (ALT), Creatinine (Cre) and Gamma Glutamyl Transferases (GGT) (p<0.001, p<0.001, p<0.001 and p<0.001, respectively). While the cut-off value of serum L-FABP for all of the patients was 5183 ng/ l {p<0.001 and Area Under Curve (AUC)0.985}, the sensitivity and specificity were 95.4% and 100%, respectively. Positive and negative predictive values for serum L- FABP were 100% and 87%, respectively. Conclusion: Serum and urine L-FABP may be a new diagnostic marker for liver damage in patients with acute hepatitis. However, our study showed that except of aminotransferases, L-FABP should be used for diagnosis of liver damage in patients with acute hepatitis, chronic hepatitis and also cirrhosis.