This study aims to investigate the link between glycated hemoglobin and diabetic complications with chronic periodontitis.A total of 207 patients with type 2 diabetes and chronic periodontitis (CP) were divided according to tertiles of mean PISA (periodontal inflamed surface area) scores as low,middle and high PISA groups.Simultaneously a group of 67 periodontally healthy individuals (PH) was recruited.Periodontal examinations,including full-mouth assessment of probing depths (PPD),bleeding on probing,clinical attachment level and plaque scores were determined.Blood analyses were carried out for glycated hemoglobin (HbA1c),fasting plasma glucose (FPG),2 h post parandial glucose (PPG).Individuals in PH group had significantly better glycemic control than CP group.Upon one-way analysis of variance,subjects with increased PISA had significantly higher HbA1c levels,retinopathy and nephropathy (P ＜ 0.05).After controlling for age,gender,body mass index (BMI),socioeconomic status (SES),family history of diabetes and periodontitis,duration of diabetes,the mean PISA in mm2,PPD 4-6 mm (％) and PPD ≥ 7 mm (％) emerged as significant predictors for elevated HbA1c in regression model (P ＜ 0.05).Logistic regression analysis revealed that PISA was associated with higher risk of having retinopathy and neuropathy (odds ratio).In our study,the association between glycemic control and diabetic complications with periodontitis was observed.