AIM: The pathophysiology underlying gastrointestinal complications of long-standing diabetes is poody understood.Recent evidence suggests an important role of intestitial cells of cajal in controlling gastrointestinal motility. The aim of this study was to clarify the changes of ultrastructural characteristics of interstitial cells of cajal in stomach of diabetic gastro-electric dysrhythmic rats.METHODS: Rats were randomly divided into diabetic group and control group, the model of diabetic rats was established by peritoneally injection of streptozotocin. Electrogastrograms were recorded and intestitial cells of cajal in antrum were observed by electrictelescopy after diabetic model rat was established for 3 mo.RESULTS: In the rats of diabetic group, the gastro-electric dysrhythmia was increased compared with control group,the abnormal rhythm index and the cofficient of variation of slow wave frequency were significantly higher than those of normal rats. The number of the gap junctions of interstitial cells of cajal in antrum of diabetic rats was significantly decreased, and the remaining structures were damaged.The organelles were also damaged, and vacuoles were formed.CONCLUSION: It is possible that changes in ultrastructural characteristics of interstitial cells of cajal in stomach are one of the mechanisms underlying gastro-electric dysrhythm in diabetic rats.