In the last years childhood obesity has reached epidemic diffusion with about 200 million school-age children worldwide being overweight or obese.Simultaneously,also the prevalence of obesity comorbidities has beenincreased and the non-alcoholic fatty liver disease(NAFLD) has become the most common form of liver disease in childhood.Also if there are some not-invasive diagnostic possibilities,the diagnostic gold standard is represented by hepatic biopsy giving to the clinicians the possibility to both diagnose the NAFLD and evaluate its progression to fibrosis or cirrhosis with greater certainty than other techniques.The use of liver biopsy in clinical practice causes debate among health care providers.Most patients with NAFLD have a good prognosis and,therefore,the risks of a liver biopsy seem to outweigh the clinical benefits.It represents an impractical screening procedure because it is both expensive and invasive and,moreover,sampling error of liver biopsy can result in substantial misdiagnosis and staging inaccuracies because histological lesions of non-alcoholic steatohepatitis are unevenly distributed throughout the liver parenchyma.The liver biopsy limitations have led the clinicians to use,also if highly imperfect,noninvasive methods to diagnose and stage NAFLD.In this editorial the main diagnostic controversies in pediatric NAFLD are examined. In the last years childhood obesity has reached epidemic diffusion with about 200 million school-age children worldwide being overweight or obese. Simultaneously also also prevailing of obesity comorbidities has been created and the non-alcoholic fatty liver disease (NAFLD) has become the most common form of liver disease in childhood. Also if there are some not-invasive diagnostic possibilities, the diagnostic gold standard is represented by hepatic biopsy giving to the clinicians the possibility to both diagnose the NAFLD and evaluate its progression to fibrosis or cirrhosis with greater certainty than other techniques. The use of liver biopsy in clinical practice causes debate among health care providers. Patients with NAFLD have a good prognosis and, therefore, the risks of a liver biopsy seem to outweigh the clinical benefits. It means an impractical screening procedure because it is both expensive and invasive and, moreover, sampling error of liver biopsy can result in substantial misdiagnosis and staging inaccuracies because histological lesions of non-alcoholic steatohepatitis are unevenly distributed throughout the liver parenchyma. the liver biopsy limitations have led the clinicians to use, also if highly imperfect, noninvasive methods to diagnose and stage NAFLD. controversies in pediatric NAFLD are examined.