Renteria, who led the Giants to its first World Series title since the franchise moved to San Francisco, said he had two reasons to sign with Dusty Baker's team: to play shortstop and to play for a contender.
"I feel happy for the opportunity to keep playing shortstop full time. That was the main reason to accept the offer from the Reds," Renteria told ESPNdeportes.com.
The deal was initially reported by ESPNChicago.com.
"We have a great team that has the talent to go to the World Series," Renteria said about the Reds' playoffs chances. "Cincinnati has some super talented youngsters that will keep getting better in the next few years. It will be a pleasure to be around for that."
Renteria said he is training in Miami to prepare for the 2011 season. The 34-year-old was placed on the disabled list three times in 2010 but finished the regular season with a .276 average and 22 RBIs in 72 games for the Giants.
"I'm getting ready to help a team for the whole year and to extend my career a few more years," said the five-time All-Star and two-time Gold Glove winner.
In the World Series, the Colombian shortstop played good defense and hit .412 with two home runs and six RBIs against the Texas Rangers.
When the season ended, the Giants declined a club option to keep Renteria for $9.5 million, and then went on to sign free-agent shortstop Miguel Tejada to a one-year, $6.5 million deal.
The Giants then offered Renteria $1 million to use him as a utility player, which Renteria rejected and immediately described as "disrespectful." However, Renteria didn't show any bitterness toward the Giants after signing with the Reds.
"San Francisco made its decision and I made mine," Renteria said. "I hope they do well and I also hope I do well."
Enrique Rojas is a reporter and columnist for ESPNdeportes.com and ESPN.com.