Non-insulin-dependent diabetes mellitus (NIDDM) is characterized by insulin resistance and impaired insulim secretion. The transgenic technology, in which a specific gene can be introduced or deleted to study its function, has been established. A number of transgenic mice, altered the expression of genes potentially involved in insulin action or pancreatic ${eta}$-cell function, have recently been developed to address questions concerning NIDDM. Thransgenic mice model may help understanding the molecular basis of complex patho-physiologies of NIDDM. This review outlines the new insights obtained from the studies of transgenic mice that overxpress or show decreased expression of putative key genes involved in the regulation of insulin resistance and pancreatic ${eta}$-cell function, therefore in the control of glucose homeostasis.