Objective This study aimed to investigate the epidemiology of diabetes in adults from Shanghai, aged 35 and older, in 2013. Methods We estimated the diabetes prevalence in a representative sample of 18,736 adults who were selected through a multistage stratified cluster sampling process. A standard questionnaire containing questions about demographic characteristics and lifestyle factors was distributed. After an overnight fast of at least 10 hours, a venous blood sample was collected from each participant. For each patient without a history of diabetes, another blood sample was drawn 120 min after an oral glucose tolerance test to identify undiagnosed diabetes and prediabetic condition. Results Among Shanghai residents aged 35 and above, the overall weighted prevalence of diabetes was 17.6% [95% confidence interval(CI): 16.4%-18.8%]. The prevalences were 19.3% in men and 15.8% in women as well as 19.1%, 15.4%, and 16.1% in urban, suburban, and rural residents, respectively. In addition, the weighted prevalence of prediabetes was 16.5%(95% CI: 15.3%-17.8%), with the prevalences of 16.5% in men, 16.6% in women, 15.2% in urban residents, 18.0% in suburban residents, and 18.5% in rural residents. Among all patients with diabetes, 68.1%(95% CI: 64.3%-71.6%) were aware of their status, 63.5%(95% CI: 60.0%-66.9%) received diabetes treatment, but only 35.1%(95% CI: 32.4%-37.8%) had adequate glycemic control. Conclusion In Shanghai, diabetes and prediabetes are highly prevalent. However, 1/3rd of diabetes cases are undiagnosed, and the rate of glycemic control is low. Objective This study aimed to investigate the epidemiology of diabetes in adults from Shanghai, aged 35 and older, in 2013. Methods We estimated the prevalence of the disease prevalence in a representative sample of 18,736 adults who were selected through a multistage stratified cluster sampling process. A standard questionnaire After an overnight fast of at least 10 hours, a venous blood sample was collected from each participant. For each patient without a history of diabetes, another blood sample was drawn 120 min after an oral Results Among Shanghai residents aged 35 and above, the overall weighted prevalence of diabetes was 17.6% [95% confidence interval (CI): 16.4% -18.8%]. The prevalences were 19.3% in men and 15.8% in women as well as 19.1%, 15.4%, and 16.1% in urban, suburban, and rural residents, respectively. In additio n, the prevalence of prediabetes was 16.5% (95% CI: 15.3% -17.8%), with the prevalences of 16.5% in men, 16.6% in women, 15.2% in urban residents, 18.0% in suburban residents, and 18.5 Among all patients with diabetes, 68.1% (95% CI: 64.3% -71.6%) were aware of their status, 63.5% (95% CI: 60.0% -66.9%) received diabetes treatment, but only 35.1 Conclusion The Shanghai glycoemic control is low. However, 1 / 3rd of diabetes cases are undiagnosed, and the rate of glycemic control is low.% (95% CI: 32.4% -37.8%