Since skeletal muscle is an important source of precursor for gluconeogenesis, it would not be surprising if carbohydrate metabolism was altered in some muscle disorders. We report a 7-10/12-year-old white male with congenital muscular dystrophy whose recurrent episodes of vomiting and dehydration were due to fasting hypoglycemia. He was found to have a blood glucose of 21 mg/dl with an episode of vomiting and dehydration. Diagnostic fasting replicated the symptoms and hypoglycemia. Associated laboratory findings included hypoalaninemia, ketonemia, and acidosis. With use of frequent feedings, there were no further episodes over 1-9/12 years of observation. To our knowledge this is the first report of hypoglycemia complicating muscular dystrophy. However, hypoglycemia may not be diagnosed because of the nonspecific nature of the symptoms. Hypoglycemia should be considered when children with reduced muscle mass develop otherwise unexplained vomiting.