Nonalcoholic fatty liver disease (NAFLD) is now considered to be the most common liver disease in the United States and involves a spectrum of progressive histopathologic changes. Common risk factors associated with NAFLD include obesity, diabetes, and hyperlipidemia. Although most patients with NAFLD have simple hepatic steatosis, a significant number develop nonalcoholic steatohepatitis, which may progress to fibrosis, cirrhosis, or end-stage liver disease. There is increasing evidence that NAFLD is a common feature in patients with the cardiometabolic syndrome, a onstellation of metabolic, cardiovascular, renal, and inflammatory abnormalities in which insulin resistance is thought to play a key role in end-organ pathogenesis. NAFLD is usually diagnosed after abnormal liver chemistry results are found during routine laboratory testing. No therapy has been proven effective for treating NAFLD/nonalcoholic steatohepatitis. Expert opinion emphasizes the importance of exercise, weight loss in obese and overweight individuals, treatment of hyperlipidemia, and glucose control.