BACKGROUND: Type 2 diabetes develops because of defects in both insulin secretion and action. The half-life of insulin in uremia is prolonged because the metabolic clearance rate of insulin in diabetic end stage renal disease (ESRD) patients is reduced with consequence that the dose of insulin and/or oral hypoglycemic agent (OHA) administered in normal renal function make them increase the risk of hypoglycemia. Therefore, we should usually reduce the dose of insulin and/or OHA, or stop administration of insulin and/or OHA if type 2 diabetic patients are progressed to ESRD. But in some patients, that is not true. The aim of this study was to test the hypothesis that insulin resistance plays an important role in (re)evaluation of optimal insulin and/or OHA dose for glycemic control after type 2 diabetic patients are progressed to ESRD. METHODS: Insulin resistance was examined in 23 type 2 diabetic ESRD patients with tight control of glycemia using the K index of the insulin tolerance test (Kitt). We divided 23 patients into three groups. Group 1 (n=10) was defined as patients who were administered neither insulin nor OHA after ESRD. Group 2 (n=9) was defined as patients who were changed from insulin to OHA as drug for glycemic control after ESRD. Group 3 (n=4) was defined as patients in whom insulin or OHA was continuously administered after ESRD without a change of them for glycemic control. We compared the degree of insulin resistance among these three groups. RESULTS: Insulin resistance determined by Kitt was significantly different between group 1 (Kitt, 2.1422/0.94-4.01%/min), group 2 (Kitt, 1.3811/0.79- 3.90%/min) and group 3 (Kitt, 0.8550/0.44-1.81%/min) by using Kruskal-Wallis test (p=0.048). Kitt in group 3 was significantly lower than in group 1 by using Mann-Whitney test (p=0.016). CONCLUSION: Although metabolic clearance of insulin is reduced by renal failure, demand of insulin/ OHA for optimal glycemic control is not reduced in higher insulin-resistant type 2 diabetic ESRD patients on hemodialysis. Insulin resistance plays an important role in determination of optimal insulin/ OHA dose for glycemic control after type 2 diabetic patients are progressed to ESRD.