Cooley says he's pretty well along in the paper worked required for filing as a candidate, but he won't make the final decision or a formal announcement until the second week in January.
Cooley first joined the county District Attorney's office as a clerk in 1973; became a deputy D.A. in 1974; and in 2000, he was elected District Attorney.
The 62-year-old Republican says all those years of experience make him well suited to assume the responsibilities of the chief law enforcement officer of the state.
The only other Republican who has declared his candidacy for the post is State Sen. Thom Harman of Huntington Beach.
Democrats considering running for Attorney General include former Los Angeles City Attorney Rocky Delgadillo; San Francisco D.A. Kamala Harris; businessman Chris Kelly, formerly of Facebook; and several state Assembly members.
Democratic incumbent Attorney General, Jerry Brown, is expected to run for governor, but he has yet to make a formal announcement.