Abstract.The results of investigations on the finite element models and test samples of flat reinforced concrete slabs of beamless frame under punching by columns of square and rectangular cross-section were shown in this paper. The research technique of reinforced concrete slabs deflections on finite element models at various loading schemes is given. Taking into consideration these results the optimum variant of load application has been chosen. Procedure and the tests results of experimental samples received, when studying of rigidity of fragments of flat reinforced concrete slabs by the action of punching force, are considered. A comparative analysis of the experimental values of the deflections of reinforced concrete slabs under punching by column of rectangular section, depending on the ratio of its sides, is completed. The research results allow to expand experimental data base as well as promote perfecting of modern positions in the theory of deformation of reinforced concrete.