We report a case of diabetic ketoacidosis with acute renal failure and elevation of pancreatic and muscle enzymes due to excess ingestion of sugar-containing soft drinks. A 12-yr-old boy suffering from consciousness disturbance was admitted to our hospital. He had had flu-like symptoms and had been consuming 1000-2000 ml of soft drinks everyday before the onset of ketoacidosis. Laboratory data on admission revealed marked metabolic acidosis, hyperglycemia, hyperosmolarity, hypernatremia, myoglobinuria, and elevated levels of creatine phosphokinase, myoglobin, blood urea nitrogen, creatinine, and pancreatic enzymes. Conventional fluid and insulin therapy were effective for these complications. Insulin therapy was discontinued within one month of hospital stay. Until this admission, there was no active intervention to resolve the problem of his family's lifestyle or to treat his obesity, therefore this neglect caused this unfortunate episode. Both medical doctors and school teachers should consider the importance of effective education and follow-up for young obese patients and intervene in childhood obesity actively. <br>