[en] A one-pot synthesis of palladium nanoparticles (Pd NPs) supported on polycarbosilane (PCS) nanowires, which also served as reducing agents, was conducted using wet and dry processing methods. Relatively small Pd NPs with diameters of approximately 2 nm and narrow size distributions were directly formed along the nanowires without aggregation owing to the on-site reduction of Pd ions. In particular, the supported Pd NPs prepared from Pd(II) acetylacetonate vapor through dry processing at a temperature of 180 °C exhibited a higher number density as compared with that of the Pd NPs fabricated through wet processing. In addition, the catalytic activity of the obtained Pd/PCS nanowires for the oxidation of CO was evaluated up to 200 °C. The CO molecules were completely converted to CO₂ in the presence of Pd/PCS nanowires even at temperatures below 120 °C. (paper)