The insulin pump is an effective glycemic control device those function is analogous to the physiologic regulation of insulin in vivo. When sufficient patient education and proper selection of patients is done, the insulin pump is one of the most effective treatment modalities for diabetic patients. However, various side effects and complications might occur during its application. We report here on an unusual case of diabetic ketoacidosis that was caused by acute inflammatory colitis and insulin pump malfunction. Peculiarly, the cause of pump malfunction was far removed from its mechanical problem. We concluded that the cause of the insulin pump malfunction was due to abdominal subcutaneous fat atrophy and the lipohypertrophied nodules of the patient that developed due to the prolonged usage of the insulin pump.