This paper suggests a new simple insulin-sensitivity index, the reverse of fasting plasma glucose and insulin product, which is significantly correlated with the insulin-sensitivity index determined by euglycemic insulin clamp technique (insulin mediated glucose disposal rate, M value) in 320 subjects of Americans including two races (r > 0.7, P = 0.0001). The analysis of 874 cases Chinese showed that the insulin-sensitivity (IS) evaluated by this new index in Chinese was similar to that determined by insulin clamp in Americans: If the IS in subjects with normal glucose tolerance defined as 1.0, then the IS in subjects with impaired glucose tolerance in Chinese and in Americans was 0.61, 0.62 (Pima Indians), 0.71 (Caucasians) and in diabetic Chinese and Americans was 0.57 and 0.53 (Pima Indians and Caucasians) respectively. Thus, it indicated this new index is fit for the evaluation of IS in Chinese population.