In the work, after a brief state of the art about push over method, the most interesting results are presented on comparison between two methods of analysis nonlinear proposed to the OPCM 3274 and his modi- fications /1/, on looms plans in ca of various heights, are presented. The comparison has focused on aspects of maximum displacement at the top and interstory, base shear and distribution of inelastic inelastic. It has been extended to frames designed with the old legislation, D.M. 16/1/96 /2/, and others frames designed with linear methods proposed to the OPCM. All designed frames were divided into three classes of height (2, 7, 12 floors) to cover several parts of the spectrum and were considered regular and irregular frames second point 4.3.1 of the OPCM said. The most clear result of this comparison is that the push over method seems to give acceptable forecasts in all aspects to chassis height not over 4 plans for those irregular and 5 plans for regular. Beyond this limit interstory drift prediction becomes unacceptable and the same fate touches to the inelastic demand forecast for 7 floors structures. A 12-storey goes into crisis also the base shear forecast, while maintaining acceptable that the maximum displacement in the summit.