As per team policy, terms of Monday's deal were not disclosed, but reports have the deal worth $40 million US.
"This is a fair deal for both Philip and the Chargers," said Chargers general manager A.J. Smith. "We're just happy to have the negotiations behind us and a bright future ahead for Philip, the Chargers and all Charger fans.
"We're looking forward to getting him on the field and ready for the 2004 season."
Rivers, who became the final first-round pick to sign, was selected with the fourth-overall pick by the New York Giants and later traded to the Chargers in a package that sent the No. 1 overall pick Eli Manning to New York.
Rivers is expected to be in uniform and practice with the Chargers Tuesday morning.
The NC State product threw for 13,484 yards, 95 touchdowns and 34 interceptions in 51 NCAA starts for the Wolfpack.
He is expected to vie for the starting position along with Drew Brees, although Brees might have the upper hand after having played well in both pre-season games.
