Polyacrylonitrile-based carbon nanofibers (CNFs) containing Ti and Mn were prepared by electrospinning. The effect of metal content on the hydrogen storage capacity of the nanofibers was evaluated. The nanofibers containing Ti and Mn exhibited maximum hydrogen adsorption capacities of 1.6 and 1.1 wt%, respectively, at 303 K and 9 MPa. Toward the development of an improved hydrogen storage system, the optimum conditions for the production of metalized CNFs were investigated by characterizing the specific surface areas, pore volumes, sizes, and shapes of the fibers. According to the results of Brunauer-Emmett- Teller analysis, the activation of the CNFs using potassium hydroxide resulted in a large pore volume and specific surface area in the samples. This is attributable to the optimized pore structure of the metal-containing polyacrylonitrile-based electrospun CNFs, which may provide better sites for hydrogen adsorption than do current adsorbates.