Clays, due to their high surface area, can act as a compatibilizing agent in some types of blends, besides modifying the properties of the final material as a whole. In the present work, a study on the influence of the addition of the clay Cloisite 20A and Halloysite in the morphology and the rheological properties of dynamically revulcanized blends composed of high-density polyethylene (HDPE)/ground tire rubber (GTR) previously devulcanized by the action of microwaves is presented. The results showed that Halloysite clay may have acted as a compatibilizing agent. Additionally, the presence of clays seems to have improved the distribution of sub-micrometer GTR particles in the HDPE matrix.