Scutaro, who will bolster San Francisco's infield, was hitting .271 with four home runs and 30 RBIs in 95 games for the Rockies.
Scutaro joins his sixth major league team. He made his major league debut with the New York Mets in 2002.
Culberson was hitting .236 with 10 home runs and 53 RBIs in his first year at Triple-A. He appeared in six games with the Giants this year, hitting .136 with one RBI.
The deal was announced after the Rockies, who are 37-61 and have the second-worst record in the National League, lost at home 3-0 to the Cincinnati Reds. Scutaro played the entire game and went 1 for 4.
"I've never been traded before during the season. I really had fun here," said Scutaro, whom Colorado acquired Jan. 11 from the Boston Red Sox for pitcher Clayton Mortensen. "I really liked it here. Unfortunately, the season didn't go the way we expected in the beginning. That's the way baseball is. It's a business and I get to go to a first-place team. It's kind of nice because all the work you put in in the offseason is to try and get a chance to play in the playoffs. I think I'm going to have that kind of opportunity with that team."
Scutaro was one of several veterans Rockies general manager Dan O'Dowd acquired in the offseason to change the clubhouse mix. Scutaro, 36, has roughly $2 million remaining on his $6 million contract and can be a free agent after the season.
"I'm going to be a free agent and hopefully have the opportunity to come back here," Scutaro said. "I think the team is going to be good pretty soon. We'll see what happens."
It's unlikely Scutaro figues in the Rockies' plans for 2013, particuarly with the arrival of impressive rookie Josh Rutledge, who is hitting .347 in 13 games with one homer and six RBIs.
The 23-year-old Rutledge has been playing shortstop because Troy Tulowitzki has been sidelined. He is expected to move to second base when he returns sometime in August and is likely to play there next season.
Scutaro said he had no idea Friday that he would be traded until given the news after the game. He said he knows fellow Venezuelans Pablo Sandoval and Henry Blanco on the Giants, "but I guess I just have to go there and find some friends."
The Giants come to Coors Field for a three-game series next Friday, which will be three days after the non-waiver July 31 trade deadline.
"They should have waited for a week," Scutaro said of the deal, "so I don't have to travel."