According to a source familiar with the deal, Beatty's deal is worth $38.75 million, taking one of the top free-agent offensive linemen off the market.
The deal includes $19 million guaranteed.
"We are very pleased to get a new deal done with Will," general manager Jerry Reese said. "We believe he is one of the ascending left tackles in the NFL."
Beatty's agents, Alan Herman and Jared Fox, declined to confirm the deal and its details when contacted Wednesday. The two sides spent part of the weekend at the combine trying to reach an agreement.
Beatty -- who turns 28 on Saturday -- took his physical and now will spend the prime of his career with the Giants.
"It's good to be home," Beatty said in a statement released by the Giants. "I'm glad I don't have any of those free agency jitters to deal with. It's settled, we're done and we're moving on. The contract is behind you -- you just have to make sure you're out there on the field and being a leader out there."
The left tackle has played in 50 games (31 starts) since being drafted by the Giants in the second round of the 2009 draft.
Beatty was a major priority for the Giants in free agency. He started 15 games this past season at left tackle despite missing most of the offseason and training camp with a back issue. With Beatty back in the fold, the Giants can focus now on re-signing starting left guard Kevin Boothe to solidify the left side of the offensive line.
"I thought I improved last year, playing the entire season," Beatty said. "I want to get back on the field and keep ascending, keep rising. The sky's the limit for me. I know there is still a lot more out there. I haven't tapped into all of my potential yet. I'm looking forward to performing and growing each year."
Tight end Martellus Bennett is also another free agent the Giants would like to have back. Reese recently released veterans such as running back Ahmad Bradshaw, defensive tackle Chris Canty and linebacker Michael Boley to clear cap space to keep young free agents like Beatty. Reese may have some more maneuvering to do to keep some of his free agents and restricted free agents like wide receiver Victor Cruz, safety Stevie Brown and running back Andre Brown.
ESPNNewYork.com's Ohm Youngmisuk contributed to this report.