On February 12, 2006, the Cincinnati Reds signed Hatteberg to a one-year, $750,000 contract. He was originally expected to give them flexibility at first base, backing up Adam Dunn. When the Reds traded Wily Mo Peña to the Red Sox, Dunn moved back to the outfield and Hatteberg was to play at first base, improving the Reds' defense.
On August 8, 2006, he recorded his 1,000th career hit against Jason Marquis of the St. Louis Cardinals at Great American Ball Park in Cincinnati. He went 3-for-5 in this game, increasing his batting average to .323.