Abstract: In order to identify risk factors of diabetes mellitus (DM), an epidemiological study was conducted during June 1997-June 1998 in two districts of Ningbo.This was carried out by stratified clusler sampling technique of target population and questionnaire survey (including laboratory detection). During this study a total of 1088 men and 1608 women were examined. The results demonstrated that the overall prevalence rate of DM was 2.52%,3.03% in male group and 2.18% in female group. Statistically, there was a significant difference in the prevalence rates between two groups (P<0.01).Meanwhile,there was also a significant difference in the prevalence rates amongs age groups (OP=4.13,OR95%CI 1.58～6.54,P<0.01),In addition,other risk factors of DM were also analyzed and discussed,and the results showed that obesity and hypertension were the key factors of DM(P<0.01).