U.S. home prices fell a record 3.4% on a seasonally-adjusted basis during the fourth quarter of 2008, according to a government index released Tuesday.

The drop surpassed the 2.0% decline reported for the third quarter and was the largest decrease in the index's 18-year history, the Federal Housing Finance Agency said.

However, home prices rose by a seasonally-adjusted 0.1% in December, after a downward adjustment for November.

The index includes sales prices of home purchases only, not appraisals for refinancings. Those data are reflected in FHFA's broader "all-transactions" home price index, which posted a more modest 0.2% drop in the fourth quarter of last year.

-By Jessica Holzer, Dow Jones Newswires; 202-862-9228; jessica.holzer@dowjones.com