Gastrointestinal disorders are common complications of diabetes mellitus and include gastroparesis, nonalcoholic fatty liver disease, gastroesophageal reflux disease, and chronic diarrhea. Symptoms of gastroparesis include early satiety, postprandial fullness, nausea, vomiting of undigested food, bloating, and abdominal pain. Gastroparesis is diagnosed based on clinical symptoms and a delay in gastric emptying in the absence of mechanical obstruction. Gastric emptying scintigraphy is the preferred diagnostic test. Treatment involves glucose control, dietary changes, and prokinetic medications when needed. Nonalcoholic fatty liver disease and its more severe variant, nonalcoholic steatohepatitis, are becoming increasingly prevalent in persons with diabetes. Screening for nonalcoholic fatty liver disease is not recommended, and most cases are diagnosed when steatosis is found incidentally on imaging or from liver function testing followed by diagnostic ultrasonography. Liver biopsy is the preferred diagnostic test for nonalcoholic steatohepatitis. Clinical scoring systems are being developed that, when used in conjunction with less invasive imaging, can more accurately predict which patients have severe fibrosis requiring biopsy. Treatment of nonalcoholic fatty liver disease involves weight loss and improved glycemic control; no medications have been approved for treatment of this condition. Diabetes is also a risk factor for gastroesophageal reflux disease. Patients may be asymptomatic or present with atypical symptoms, including globus sensation and dysphagia. Diabetes also may exacerbate hepatitis C and pancreatitis, resulting in more severe complications. Glycemic control improves or reverses most gastrointestinal complications of diabetes.