The present work describes the synthesis and characterization of polyurethane (PU), polyaniline (PANI) and three IPNs (90/10, 80/20, 70/30) ratios were characterized by Fourier transformed infrared (FTIR) to analyze the generated functional groups of the synthesis. The combination PU/PANI was accomplished through the interconnection of the two polymers via condensation of PU prepolymer terminal NCO groups and the amine groups of PANI. DMA studies indicated that the PU had higher glass transitiontemperatures (Tg) with the increase of PANI. SEM micrographics were obtained to 1000X of the PU, PANI and the ratios 90/10, 80/20 and 70/30 of PU/PANI. A morphological interpretation was proposed in which PANI chains formed a phase dispersed in a PU matrix, linked together by an interphase, that could be responsiblefor the connectivity between the two polymers and determine excellent mechanical properties.