Objective To study the periodontal status and risk factors for periodontitis in periodontitis patients at different ages in wuhan. Methods From January 2007 to March 2008, the cross-sectional survey on periodontal conditions of 493 physical examinees in Wuhan city was carried out with random cluster sampling method. 458 cases of them were in accordance with the inclusive criteria and were stratified into two groups: young and middle-aged adults (aged 30-59 years) and old adults (aged 60 years and over). A case-control study was carried out in the periodontitis cases group (n=280) and the control group (n=178). Database was created by SQSERVER2000 and SPSS11.0 was used for statistical analysis. The relationship of periodontitis with age, gender, nation, educational background, diabetes mellitus, smoking, drinking, mental pressure and oral hygiene habits were analyzed by univariate and multivariate logistic regression analysis. Results The prevalence of periodontitis was 61.1% (280/458). Univariate analysis revealed that age, educational background, diabetes mellitus, smoking and oral hygiene habits were related factors for periodontitis (OR:0.44, 2.27, 3.44, 1.75, 9.82, P<0.05 or P<0.01). Meanwhile, multivariate analysis showed that suffering from diabetes mellitu and low educational background were the independent risk factors for periodontitis (OR=2.66, 1.95, all P<0.05). After stratification by age, multivariate logistic regression analysis showed that there was no correlation between diabetes mellitus and periodontitis prevalence in young and middle-aged adults and diabetes mellitus was a risk factor for periodontitis in old adults(OR=6.91, 95%CI: 1.27～37.42). Conclusions There are many risk factors for periodontitis and diabetes plays a major role in the development of periodontitis in old adults.