The 65-year-old commissioner will step down in July after 16 years, his tenure marked by labor harmony and unprecedented riches through television deals.

Tagliabue has been in charge since 1989, when he succeeded Pete Rozelle, and agreed last March to stay to complete the TV deal and a long-term contract with players.

He finally got that done 12 days ago, finishing the most arduous labor negotiations since the league and union agreed on a free agency-salary cap deal in 1992.

"I really want to emphasize how much of a privilege it is to spend most of your adult life with the NFL. This is not an easy decision for me," Tagliabue said on a conference call Monday.

"As difficult as this decision is, I also know it's the right decision. Right for me. Right for the league," he said.

Roger Goodell, the NFL's chief operating officer, and Atlanta general manager Rich McKay are the two leading candidates to succeed Tagliabue. Baltimore Ravens president Dick Cass also is considered to have an outside chance and Secretary of State Condoleeza Rice has said she would like the job.

"Ask her," Tagliabue said when quizzed about Rice's candidacy.

Tagliabue siad the search is wide open and that he will stay on beyond July to avoid the kind of seven-month deadlock that occurred between him and the late Jim Finks after Rozelle stepped down in March 1989.

Owners will begin to look for a new commissioner at their meetings next week in Orlando, Fla.

As for his own tenure, Tagliabue said, "Building a strong relationship with the NFL Players Association is the thing I'm most proud of."

"Everyone involved in the NFL in the '80s saw that as a negative," he said.

More than anything else, Tagliabue took over a league that already had already become America's game under Rozelle and took it to the next level, enriching it and restoring labor peace.

In many cases, he turned millionaire owners into billionaires. The value of many franchises has increased tenfold since 1989 — those worth $70 million then are worth $700 million now.

With the labor and TV deals done, Tagliabue made no secret that retirement was near.

Last week, he told players' union executive director Gene Upshaw that he would spend the weekend at his vacation home in Maine. Tagliabue also said he might look at buying a boat for retirement.

Upshaw heard about Tagliabue's decision while vacationing in Hawaii, and e-mailed him: "I didn't expect I'd start my Monday morning this way. I guess you bought the boat."

Turns out Tagliabue didn't — although he did go shopping.

Tagliabue's first phone call with the news went to Pittsburgh's Dan Rooney, the NFL's senior owner. The other owners learned of it by e-mail.

"We've got the best labor deal in sports. We've got the best league. He's been our leader. The whole way he's done this has been wonderful," Rooney told The Associated Press.

Tagliabue will stay on with the NFL as a senior executive and a consultant through 2008, part of the contract extension he signed last July.

His term will be remembered most for labor peace following strikes in 1982 and 1987. His close relationship with Upshaw finally led to a long-term agreement after five years without a contract.

But the bargaining was hard this time, with three straight deadline extensions needed. The agreement avoided the prospect of entering free agency this year with the possibility of an uncapped year in 2007.

It came at the expense of revenue sharing among the owners, an issue that had divided high-revenue and small-revenue teams and contributed to the deadlock. He did it with what has been considered his greatest skill as commissioner, patching together a coalition of nine teams with differing viewpoints to reach a compromise considered satisfactory by all but two teams.

He also oversaw a massive stadium building program. More than two-thirds of the NFL's 32 teams are either playing in or building stadiums that didn't exist when he took over as commissioner in 1989.

He said his biggest regret as commissioner was allowing both the Rams and Raiders to leave Los Angeles after the 1994 season — the Rams for St. Louis and the Raiders for Oakland. The league has been trying to get a team back in Los Angeles since then.

Before taking on this job, Tagliabue was a league lawyer who spent much of that time as the NFL's representative and unofficial lobbyist in Washington.

"We didn't always agree, but he encouraged the airing of different opinions and philosophies amongst the entire ownership," Dallas owner Jerry Jones said. "From a personal perspective I know he brought out the best in me in what I could do to serve the NFL and the fans of this league. That's leadership."