The authors have reported several papers on the warm compacted automotive P/M sprockets with normal sintering and high temperature sintering. Warm compacted and normal temperature sintered sprockets are applied to roller chain system in non-DIG (Direct Injection Gasoline) engines. Warm compacted and high temperature sintered sprockets are applied to silent chain system in DIG engines. This time we won the JSPM technology development award on these new sprockets, so we summarize the background and the history of this development.