The purpose of this paper is to develop a method of stress and deformation analysis of body structures (sedan, station wagon, and so on). Many of these are reinforced shell structures, but they contain enormous structural “cut-outs”. An attempt is made to analyze them as structures consisting of both rigid frames and reinforced shells. In order to check the validity of this method, experiments are carried out on model and actual structures. In the former, comparison between the calculated results and the tests indicates that the agreement of stress and deflection is good, and in the latter, fairly good.