CKDO is a Canadian clear-channel radio station, broadcasting at 1580 AM in Oshawa, Ontario. The station airs an oldies format. CKDO also has an FM rebroadcaster (CKDO-FM-1) at 107.7 FM. CKDO was launched in 1946 by T. W. Elliott, an executive with the Canadian division of General Motors. Its original frequency was 1240.