Maddux, who turns 43 in April, ranks eighth on the career wins list with 355. He went 8-13 with a 4.22 ERA last season with the San Diego Padres and Los Angeles Dodgers.
Maddux made three relief appearances in the playoffs for the Dodgers this year -- he had an 0.00 ERA over four innings -- and then filed for free agency amid speculation he would retire.
On Friday, confirmation came from the office of Maddux's agent, Scott Boras. Maddux, his family and Boras will hold a news conference at the hotel where the meetings are being held to announce one of baseball's greatest pitchers is finished.
Last month, Dodgers general manager Ned Colletti left open the possibility that Maddux would return for a 24th season in the majors.
"I told Scott we'd love to have him back, and we're not going to be closing the door on Greg Maddux anytime soon," Colletti said at the time. "I've known him for a long, long time. I respect who he is and admire him for what he's done. I know the impact he has on a club and on a franchise."
Maddux finished one win ahead of Roger Clemens on the career victory list. Overall, "Mad Dog" was 355-227 with a 3.16 ERA, and is considered a certain first-ballot Hall of Famer when he becomes eligible after five years.
Noted for impeccable control, Maddux won Cy Young Awards from 1992-95 and earned a record 18 Gold Gloves while with the Chicago Cubs, Atlanta, Dodgers and Padres.
Maddux was an eight-time All-Star and won at least 13 games in 20 straight seasons, a streak that ended this year.
The last-place Padres traded Maddux to the Dodgers on Aug. 19 for two minor leaguers to be named or cash, and went 2-4 in seven starts for Los Angeles. His last start for the NL West champions was a gem -- he beat San Francisco, giving up one run and two hits in six innings.
"He's remarkable," Dodgers manager Joe Torre said after the 2-1 victory. "I've watched and admired him from across the field. Tonight was, you could say, vintage."
Said Maddux following the win: "In all honesty, I have felt this game has given me more than I ever thought it would in the first place. I just wanted to have a good game. I haven't had many since I got here."
While Maddux finished on the West Coast, he will always be associated with top teams in Atlanta. Along with fellow 300-game winner Tom Glavine and John Smoltz, Maddux helped the Braves win division titles for more than a decade, and they won their lone World Series championship there in 1995.
Glavine and Smoltz are both in their 40s and coming off arm operations, and their futures are in doubt. Longtime teammates on the field and golfing buddies away from the field, there has long been talk that Atlanta's Big Three might someday be reunited -- with election to the Hall on the very same day.
Maddux made his major league debut in September 1986 with the Cubs. As a pinch-runner, in fact. He wound up losing that game in relief.
His brother, Mike, started his big league career three months earlier as a pitcher for Philadelphia. He recently was hired as Texas' pitching coach.