Abstract： Objective The significance of erythrocyte sodium lithium countertransport activity (SLCA) in type 2 diabetes with or without hypertension and diabetic microvascular complications was investigated.Methods SLCA was measured according to the method described by Fujita in 81 type 2 diabetes and 40 healthy control subjects.Results The results showed that SLCA was significantly higher in type 2 diabetes (0.361±0.139 mmol·L -1 ·RBC -1 /h) than that in healthy control subjects (0.191±0.083 mmol·L -1 ·RBC -1 /h)( <0 01).In type 2 diabetes with hypertension and (or) microvascular complications (retinopathy and/or nephropathy),SLCA was significantly higher than uncomplicated diabetes or control subjects ( P <0 05 or P <0 01).A stepwise multiple regression analysis was conducted using SLCA as the dependent variable.It was found that SLCA was positively correlated with complication variable ( P <0 01) and was inversely correlated with the insulin sensitivity index (ISI) ( P <0 01).Conclusion This study suggested that ① erythrocyte SLCA was increased significantly in type 2 diabetes;②erythrocyte SLCA was significantly higher in type 2 diabetes with hypertension and microvascular complications than that in type 2 diabetes without these complications,and the elevation of SLCA might reflect the serious degrees in type 2 diabetes complications,and these were related with insulin resistance.