['To explore demographic and metabolic factors associated with increased alanine aminotransferase (ALT) activity in non-diabetic non-alcoholic fatty liver disease (NAFLD) patients.', 'Overall 372 patients who consecutively attended to Gastroenterology Clinic of Baqiyatallah University of Medical Sciences, Tehran, Iran awere diagnosed as NAFLD entered into analysis. Exclusion criteria were having diabetes mellitus and fasting blood glucose over 126 mg/dL, active hepatitis B virus infection, having hepatitis C virus positive serology, and to be under corticosteroid therapy. ALT levels were considered pathologically high when it was over 30 IU/L for men and over 19 IU/L for women.', 'Bivariate analyses using t test and chi-square test showed that patients with pathologically augmented ALT levels had significantly higher NAFLD grades in their ultrasonographic evaluations (P=0.003). Moreover, these patients represented significantly higher homeostatic model assessment levels (P=0.003), levels of serum insulin (P=0.002), fasting blood glucose (P<0.001), and uric acid (P=0.02). The prevalence of insulin resistance was also higher in patients with increased serum ALT concentrations. Multifactorial logistic regression models showed that ultrasonographic grading of NAFLD (P=0.027) and insulin resistance (P=0.013) were the only variables significantly associated with abnormal ALT levels.'] Is elevated alanine aminotransferase activity associated with dyslipidemias , but related to insulin resistance and higher disease grades in non-diabetic non-alcoholic fatty liver disease?