mice of NOD inbred strain were observed for their diabetes from 3 to 52 weeks old.Total cumulative diabetes incidence in males was 28.3%,lower than that 50% in females Abrupt onset occurred among 10-33 weeks old,while male's onset was later than female's After 45 weeks old,few onset individuals could be found.The diabetic animals died within 2-5 weeks after the onset.Clinical features of the affected animals were glycosuria,hyperglycetemia,polydipsia,polyuria,polyphagia and body weight loss.Severe lymphocytic infiltration in the pancreatic islet was observed in prediabetic and diabetic animals.Insulin dependent diabetes mellitus (IDDM) of NOD mice was an autoimmune disease.NOD mice could be used as a model for human IDDM.