A comprehensive study has been conducted to evaluate the hydrogen uptake capacity of carboxylate functionalized multi-walled carbon nanotubes (f-MWCNTs) after strategic incorporation of Fe and Cu nanoparticles on the surface. Metal decorated multi-walled carbon nanotubes (Fe f-MWCNTs and Cu f-MWCNTs) were prepared by refluxing various concentrations of metal precursor and f-MWCNTs in different reaction medium such as water, amine and DMF. The prepared materials were characterized by FT-IR, powder XRD, SEM, TEM and BET analyzer. The adsorption isotherms revealed that the hydrogen storage capacity of Fe f-MWCNTs and Cu f-MWCNTs was 0.55 and 0.68 wt%, respectively, at 253 K and 70 bar. Similarly, both compounds showed 0.39 and 0.5 wt% adsorption at 298 K and 70 bar, respectively. The uptake of hydrogen by metal decorated multi-walled carbon nanotubes was remarkably enhanced by a factor of 2 and 5 times that of Pristine MWCNT at 253 K and 298 K, respectively. (C) 2016 Hydrogen Energy Publications LLC. Published by Elsevier Ltd. All rights reserved.