Diabetes mellitus is an iceberg disease. It is one of the greatest challenges and threats of this century that will be faced by the whole Human race in near future. It is now seen as a heterogenous group of diseases. It is a long term disease with variable clinical manifestations and progression. Chronic hyperglycemia leads to a number of complications - cardiovascular, renal, neurological, ocular and intercurrent infections. It imposes a great burden of morbidity and associated medical cost incurred on those affected and their family and thereby on the community. Diabetes mellitus is the Emerging Epidemic of the world of 21st century. It affects both the developed and developing countries of the world. It poses a heavy financial burden to both the affluents and the poor of the world. In this book we want to estimate the prevalence of diabetes mellitus among 35 years adult slum dwellers of Kolkata (urban slum population of Chetla); determine the association of the biosocial risk factors with diabetes mellitus among the study population; assess the awareness about diabetes mellitus among the study population.