The viscoelastic properties of composites multi walled carbon nanotube / epoxy at different weight fractions (0.1, 0.5 and 1wt %) were evaluated by performing dynamic mechanical thermal analysis (DMTA) test. The MWCNT/ epoxy composite were fabricated by sonication and a cast molding process. The results showed that addition of nanotubes to epoxy had a significant effect on the viscoelastic properties. However, the use of 0.5wt% increased the viscoelastic properties more significantly. Concerning viscoelastic modeling, the COLE-COLE diagram has been plotted by the result of DMTA tests. These results show a good agreement between the Perez model and the viscoelastic behavior of the composite.