TiO₂-supported platinum and cobalt catalysts were prepared by co-impregnation. The catalytic characteristics of these catalysts were studied by XRD and H2-TPR and then catalytic activities were measured for SCR of NO with H₂. The activity at 100℃ of Pt-Co(3)/TiO₂ was distinctly higher than those of Pt/TiO₂ and Co(3)/TiO₂. The reducibility of Co₃O₄ particles and interaction between platinum and cobalt may be related to the high activity of Pt-Co(3)/TiO₂. The activities at 100℃ of Pt-Co/TiO₂ catalysts increased between 0.5% and 1.0% of H₂ concentration regardless of Co content, however the activities of Pt-Co/TiO₂ catalysts were kept constant between 1.0% and 1.5% of H₂ concentration. This result may be related to large amount of H₂O produced could impede the catalytic activity, although the reduced state of particle surfaces of Pt and Co was more stable with H₂ concentration. The NO selectivities to N₂O of Pt-Co/TiO₂ catalysts were approximately 50% regardless of Co content and H₂ concentration.