Metal-carbon nanotube-graft-polymer (MCNT-g-P) nanocomposites were synthesized and characterized successfully. In this work, multiwall carbon nanotubes (MWCNT) were opened using HNO3/H2SO4 mixture and filled by metal nanoparticles such as silver nanoparticles through wet chemistry method. Then MWCNT containing metal nanoparticles were used as macroinitiator for ring opening polymerization of ε-caprolactone and MCNT-g-P nanocomposites were obtained. Length of grafted polymer arms onto the MWCNT was controlled using MWCNT/ε-caprolactone ratio. Structure and properties of nanocomposites were evaluated by TEM, DSC, TGA, and spectroscopy methods.