Diabetic Ketoacidosis(DKA), one of acute complications of diabetes mellitus(DM) occurs mostly in insulin dependent diabetes mellitus (IDDM) patients. Its clinical symptoms are hyperglycemia, ketonemia or ketonuria, metabolic acidosis, etc. The interaction of lack of insulin, excessive secretion of insulin antagonic hormone and dehydration cause body fluid loss and electrolyte, typical symptom of DKA as polyuria, polydipsia, nausea, vomiting, abdominal pain occur. As a result, prompt supply of fluid and insulin by intravenous injection should be conducted for treatment. It is still an emergent disorder whose mortality is still 10 to 15%, though is has decreased compared to the past. We treated a female patient who has DKA, had withdrawn insulin pump therapy. We report a case of DKA with a brief review of related literatures.