The present invention relates to a combination drug comprising gemigliptin and metformin as active components and a method for the preparation thereof. The pharmaceutical composition consisting of a first layer comprising metformin and a second layer comprising gemigliptin according to the present invention has a superior effect on the prevention and treatment of diabetes and their complex diseases, and reduces the adverse effects of each component. In addition, the present composition comprises gemigliptin and metformin in a separated form so as to maintain the inherent dissolution rates of both components and improve patient compliance.