This work reports the hydrogen uptake capacity of V-capped and V-inserted VC3H3 organometallic complexes using density functional theory (DFT) with different exchange and correlation functionals. Maximum of five and three H-2 molecules are adsorbed on V-capped and V-inserted VC3H3 structures, respectively. This corresponds to the hydrogen uptake capacity of 10.07 and 6.66 wt% for the former and the latter, respectively. The first added hydrogen molecule is adsorbed in dihydride form on V-capped as well as V-inserted VC3H3 complex. A complex with a dissociated hydrogen molecule adsorbed has higher binding energy than that of molecular hydrogen adsorbed. The nature of interactions between H-2 molecules and organometallic complex is studied using many-body analysis approach. Thermo-chemistry calculations are performed to see whether H-2 adsorption on V-capped complex is energetically favorable or not for room temperature hydrogen storage. (C) 2010 Professor T. Nejat Veziroglu. Published by Elsevier Ltd. All rights reserved.