Alcoholic liver disease (ALD) and non-alcoholic fatty liver disease (NAFLD) are commonest causes of chronic liver disease in developing as well as developed countries. Their incidence has increased due to widespread easy availability of alcohol and sedentary life style of people. NAFLD is a spectrum which includes fatty liver (NAFL) which is considered benign disease, steatohepatitis (NASH) which indicates ongoing injury to liver and cirrhosis of liver. Similarly, ALD spectrum comprises simple steatosis, alcoholic hepatitis, and cirrhosis and its complications. Most of the time there is significant overlap between these diseases and clinical presentation depends upon the stage of liver disease. Most of the NAFLD patients are asymptomatic and diagnosed to have fatty liver while undergoing routine health check up. ALD requires significant history of alcohol intake which is supportive by radiological and biochemical tests. In both NAFLD and ALD patients, liver enzymes are seldom raised beyond five times the upper limit of normal. Liver biopsy is required for diagnosis of NASH as it is a histological diagnosis and sometimes in alcoholic hepatitis for confirmation if diagnosis is in doubt. Non-invasive markers and prognostic scores have been developed for avoiding liver biopsy in assessment and treatment response of NASH and alcoholic hepatitis patients.