AIM: There is still no accepted conclusion regarding the clinical features and related risk factors of patients with fatty liver. The large-scale clinical studies have not carried out yet in Guangzhou area. The aim of the present study was to investigate the clinical features and related risk factors of patients with fatty liver in Guangzhou area. METHODS: A total of 413 cases with fatty liver were enrolled in the study from January 1998 to May 2002. Retrospective case-control study was used to evaluate the clinical features and related risk factors of fatty liver with logistic regression. RESULTS: Obesity (OR: 21.204), alcohol abuse (OR: 18.601), type 2 diabetes mellitus (OR: 4.461), serum triglyceride (TG) (OR: 3.916), serum low-density lipoprotein cholesterol (LDL-C) (OR: 1.840) and fasting plasma glucose (FPG) (OR: 1.535) were positively correlated to the formation of the fatty liver. The levels of serum alanine aminotransferase (ALT) and gammaglutamyltransferase (GGT) increased mildly in the patients with fatty liver and were often less than 2-fold of the normal limit. The higher abnormalities of aspartate aminotransferase (AST) levels (42.9%) with AST/ALT more than 2(17.9%) were found in patients with alcoholic fatty liver (AFL) than those with nonalcoholic fatty liver (NAFL) (16.9% and 5.0% respectively). The elevation of serum TG, cholesterol (CHOL), LDL-C was more common in patients with NAFL than with AFL. CONCLUSION: Obesity, alcohol abuse, type 2 diabetes mellitus and hyperlipidemia may be independent risk factors of fatty liver. The mildly abnormal hepatic functions can be found in patients with fatty liver. More obvious damages of liver function with AST/ALT usually more than 2 were noted in patients with AFL.