Abstract： Objective To show prevalent features and odds ratio as well as attributive risks of diabetes mellitus and impaired glucose tolerance with age increment in the middle and old age population.Methods We used cross over section epidemiology survey throughout random stratified population sampling, comparing prevalent characteristics of diabetes and IGT in the 2354 population aged more than 40 in 4 communities in Beijing in 1997.Results The diabetes prevalence rising with aging of population has been showed by correlation of diabetes prevalence to middle and old aged populations (DM:r=0 99,P=0 002; IGT:r=0 92,P=0 029). By rank sum test, the mean blood glucose levels in the population and the patients with IGT varied significantly among age groups (IGT: χ 2=9 816, P=0 044,total:χ 2=106 944,P<0 0005). Both prevalence and odds ratio of diabetes or IGT in the population were increased with age increment. There appeared 3 different age stages with distinct prevalence and odds ratio of diabetes and IGT: 40 years old group(DM:4 95%,OR=0 41;IGT:8 35%,OR=0 66);50～69 years old(DM:12 13～13 57%,OR=1 08～1 22;IGT:11 02～13 60%,OR=0 89～1 13);and 70～99 years old(DM:19 02～21 05%,OR=1 83～2 08;IGT:19 01～21 05 %,OR=1 69～1 92). All results support the prevalence and odds ratio increasing with age rising in middle and old aged population.Conclusion Patients with diabetes and IGT are accumulating with age increment in the middle and old aged population. It showed that age increment is an independent risk factor for diabetes and IGT in middle and old age population.