With 3-story and 6-story RC buildings of ductile frames, previously designed, non-linear static analysis with increased monotonically lateral loads (Push-over) are made in order to determine its collapse and their responses against the inelastic seismic analysis results with the SCT-EW-85 record are compared. It is designed with the Principal Body and with the Appendix A conditions of the Seismic Technical Norms of the Mexico City Code (RDF-04), satisfying the maximum story distortion limits of the service and collapse conditions; the buildings (offices) are in the IIIb compressible seismic zone. The non-lineal responses were determined with nominal resistance and over-resistance effects. For the non-linear static analysis with increased monotonically lateral loads, was important to select the type of lateral forces distribution. The comparison were made with base shear force–roof lateral displacement relations.