In this work a functionalised polymer was studied and a polymeric matrix was chosen as a base with the aim of producing both a low cost and low weight hydrogen storage material. A poly-ether-ether-ketone (PEEK) was chosen as a base polymeric matrix and functionalised in situ by manganese oxide formation. The functionalisation process and the preliminary results on hydrogen storage capability of the synthesized polymer are reported. The polymer was characterized by scanning electron microscopy, transmission electron microscopy, X-ray diffraction, BET method surface and gravimetric hydrogen adsorption measurements. The metallic compound introduction modifies the morphology of the material and supplies an increased surface area for hydrogen chemisorptions, revealing a 1.2 wt% hydrogen adsorption capability at 77 K. Preliminary results from gravimetric measurements showed that by increasing the temperature hydrogen storage capability was reduced but not eliminated; for example, a 0.24 wt% at 50 degrees C and 60 bar was obtained. Moreover, reversibility of hydrogen adsorption and desorption in a wide range of both temperatures and pressures was confirmed. For this reason this approach is considered promising and deeper studies are in progress. Copyright (c) 2011, Hydrogen Energy Publications, LLC. Published by Elsevier Ltd. All rights reserved.