Amrita Diabetes and Endocrine Population Survey (ADEPS) was conducted as a community-based cross-sectional survey to assess the prevalence of undetected diabetes mellitus (DM) and impaired glucose tolerance (IGT) and their possible relationship with various risk factors in an urban South Indian population. An initial house-to-house survey of adults between ages 18 and 80 years (n = 3069) was followed by a second phase consisting of health check-up and biochemical evaluations of participants (n = 986). DM and IGT were diagnosed as per WHO criteria. Reported prevalence of known diabetes mellitus in the survey was 9.0% (276/3069); (M-8.7% and F-9.2%). Among the screened subjects who underwent blood testing, the prevalence of newly diagnosed diabetes was 10.5%. The prevalence of IGT was 4.1% and IFG was 7.1%. Increasing age, obesity, positive family history of diabetes, abnormal subscapular triceps skin fold ratio and presence of acanthosis nigricans (AN) were all found to be associated with increased risk of DM. The finding of high prevalence of newly detected DM and IGT in this population of Kerala with the highest standards of health care and literacy level compared to other states of India, emphasizes the need for routine screening of high-risk groups for early detection of the disease. A simple cutaneous sign, acanthosis nigricans was independently associated with increased risk of type 2 diabetes in this survey and can be used as indication for screening for DM and IGT.