Obesity – Are we continuing to play the genetic “blame game”? Venkatesan Radha,1 Viswanathan Mohan1,2 1Department of Molecular Genetics, Madras Diabetes Research Foundation, 2Dr. Mohan’s Diabetes Specialties Centre, WHO Collaborating Centre for Noncommunicable Diseases, Prevention and Control, IDF Centre for Education, Gopalapuram, Chennai, India Abstract: Obesity is a heterogeneous disorder, its biological causes being complex. The escalating frequency of obesity during the past few decades is due to environmental factors such as sedentary lifestyle and overnutrition, but who becomes obese at an individual level is determined by genetic susceptibility. Understanding of the molecular cause of obesity is still in its infancy. More research is needed in the area of obesity genetics and epigenetics before formulating public health prescription as presently it would not be cost-effective. This review delineates monogenic form of obesity and the multifactorial nature of common forms of obesity, due to the interaction of genes, environment, and lifestyle. Keywords: obesity, genes, genomics, monogenic obesity, polygenic obesity