Pt catalysts were prepared by encapsulating the active metal in the NaA zeolite structure. The catalysts were prepared by hydrothermal synthesis using two heating sources, conventional heating through a thermal bath and microwave radiation. The synthesis time was significantly reduced using microwave radiation without affecting the crystallinity or metallic content of the solids obtained. By X-ray diffraction the presence of the pure NaA zeolite phase was confirmed in all the samples. XRD, XPS and TEM results suggested the presence of Pt particles preferentially located inside the crystalline structure. Pt_NaA catalysts were active and selective for the water gas shift reaction at 673 K. No methane formation was detected in any of the samples under the reaction conditions studied. The Pt_NaA catalyst with low Pt content (0.6% wt.) achieved a high conversion of CO (ca. 70%).