This article presents the structural and mechanical characterization of a TRIP (transformation induced plasticity) effect steel. The study contains a detailed microstructural analysis and its influence in bending, stress-strain, and fracture tests. The results show that a high value for yield strength and a limited hardening capability, are due to a high content of carbon and the prominent fraction of the initial martensite phase in the steel before strain. The obtained metalographies show that the reorganization of the microstructural phases is related with the level of deformation and the orientation of these phases towards the applied stress.