Type 2 Diabetes Mellitus (T2DM) is the predominant form of diabetes worldwide and much is known about its patho-physiology. Yet, newer aspects related to it are being constantly explored. For ages, testosterone has been known as the male sex hormone but now it has been shown by certain studies that it might have a role in the development of metabolic disorders like Type 2 Diabetes Mellitus. This study was carried out to determine the relation of testosterone levels with Type 2 Diabetes Mellitus and lipid profile in North East Indian men aged 31 to 73 years. The findings support the hypothesis that low testosterone might have a role in the development of T2DM and to the associated altered lipid profile. This study, though a small one is among the few of its kind in India and it thrives to assist other studies related to the matter. I am really thankful to Mr. M.S.Khaund,my husband, Dr.K.Bhattacharyya,Head of Department of Biochemistry, Gauhati Medical College, Assam, and my colleagues, Dr.D. Patgiri and Dr.E.T.Jahir for their continuous support in publishing this book.