The NFL referees union formally ratified Saturday a contract with the league that had been agreed upon earlier this week.
The approval marks an official end to the lockout, said spokesman Greg Aiello of the National Football League.
Even before the formal vote, the officials returned to work in Thursday night's game in Baltimore between the Ravens and the Cleveland Browns. The Ravens won, 23-16.
The new eight-year contract -- the longest ever for officials, according to the NFL -- gives the union referees a pay bump from $149,000 a year in 2011 to $173,000 in 2013. The pay will rise to $205,000 by 2019.
The agreement keeps their pension program in place for five years.
The contract allows the NFL to hire some officials on a year-round basis and hire additional referees so they can be trained.
This season's use of replacement referees climaxed in a furor over a botched call that allowed the Seattle Seahawks to walk away with a 14-12 victory against the Green Bay Packers in a nationally televised game Monday night.
In what became a widely mocked symbol of the quality of officiating by the replacements, a photo from that game shows two officials in the end zone displaying competing signals: one indicating a touchdown, the other an interception.
The result generated intense and immediate criticism of the league. Even President Barack Obama weighed in Tuesday urging a quick resolution. On Thursday, White House spokesman Jay Carney said Obama was "very pleased" with the preliminary resolution.
Commissioner Roger Goodell said he was not surprised by the outcry about the Monday night game.
The league acknowledged Tuesday that the Packers should have won, but allowed the result of the game to stand.
The return of the league's regular referees won't put an end to controversial calls, said retired NFL player Tiki Barber. But it will raise the respect level between coaches and players and officials, Barber said.
"There's still going to be arguing with referees," he said. "They're still going to make bad calls. But now we're going to know that it's coming from a base of knowledge. These guys know what they're talking about and they're going to have an argument for why they do what they do on the field."