Aim: Simple, rapid, and non-invasive methods for the early diagnosis of non-alcoholic steatohepatitis (NASH) in patients with fatty liver are an unmet need in clinical practice. Transient elastography (TE), commonly used for measuring liver stiffness (LS), which is significantly influenced by both liver fibrosis and inflammation is a promising tool.Methods: We studied retrospectively the impact of TE in a cohort of 98 consecutive asymptomatic patients with fatty liver who underwent a liver biopsy [21 non-alcoholic fatty liver (NAFL) and 77 NASH] and TE on the same day at the Hepatology Unit of University Hospital of Pisa. Patients positive for HBsAg, anti-HCV, HIV, autoantibodies, drug-induced liver disease, Wilson's disease, hemochromatosis, alpha-1 antitrypsin deficiency, type 2 diabetes, or neoplasia were excluded. Results: NAFL patients were younger (42.5 years vs. 47.7 years, P = 0.02) and with lower BMI (25.5 kg/m2 vs. 28.8 kg/m2, P < 0.001) than NASH patients. TE was higher in NASH than NAFL patients (8.1 kPa vs. 5.4 kPa, P = 0.01). Age, BMI, TE, and total/LDL cholesterol were statistically significantly different between NAFL and NASH patients, but with multivariate analysis only BMI (P = 0.009) and TE (P = 0.031) were independent predictors of NAFL/NASH with AUROCs of 0.771 and 0.754, respectively. A score combining TE and BMI (TE*BMI) showed the best AUROC (0.817, by De Long test, P = 0.01) to differentiate NAFL/NASH (P = 0.005).Conclusion: Ultrasound based LS measure qualifies as a candidate tool for the early screening of NASH in fatty liver patients provided that its measure is properly standardized and tested in large prospective studies enrolling patients with different clinical and histological features.