Samuel's agent, Alonzo Shavers, was able to negotiate a 3 year, $18.5-million deal which was agreed upon by both teams on Wednesday.
The Eagles will get a 7th round draft pick for Samuels. The Eagles now have 10 picks in the upcoming NFL draft.
Samuel's contract with the Eagles called for him to earn $9.9 million in 2012 and $11.4 million in 2013.
Falcons general manager Thomas Dimitroff was New England's director of scouting when the Patriots selected Samuel in the fourth round in 2003. When asked about Samuel's interest in the Falcons, Shavers noted the cornerback's connection to Dimitroff.
"Here's what I will tell you," Shavers said. "Atlanta is run by someone who brought him into the league, so you can take it from there."
Samuel, 31, would give Atlanta a strong trio at cornerback with Dunta Robinson and Brent Grimes under new defensive coordinator Mike Nolan.
Grimes signed his franchise tag tender on Tuesday. Grimes will make $10.262 million this season.
The Falcons have six picks, but no first-round selection in the NFL draft.
Samuel became expendable when the Eagles signed Nnamdi Asomugha and acquired Dominique Rodgers-Cromartie last July, giving them three Pro Bowl cornerbacks. But the team couldn't find a suitable deal for Samuel, so they kept him and used Rodgers-Cromartie in the nickel spot.
While Asomugha and Rodgers-Cromartie struggled in a new defense and new roles, Samuel was the most consistent of the trio. The outspoken Samuel probably sealed his fate in Philadelphia when he criticized the front office at the trade deadline, saying management was "playing fantasy football with the owner's money."
Samuel has 45 career interceptions in nine seasons. He had three interceptions in 14 games last season.
AP Sports Writers Charles Odum and Rob Maaddi contributed to this report.