In patients with acromegaly, glucose intolerance and diabetes mellitus are one of the frequent manifestations. And the type of diabetes in these patients is usually non-insulin dependent type secondary to insulin resistance caused by growth hormone excess. Therefore, the diabetes mellitus in these patients dose not tend to develop diabetic ketoacidosis. But we experienced and presented the case of a patient with acromegaly hospitalized due to the diabetic ketoacidosis without overt clinical manifestations of acromegaly. This case of acromegaly showed that growth hormone excess could cause diabetic ketoacidosis in the presence of relative insulin deficiency.