From December 2009 to December 2010, home prices fell in 18 of 20 cities tracked in the report.
Only San Diego and Washington showed prices higher in December compared to a year earlier. Over the year, prices rose 1.7 percent in San Diego and 4.1 percent in the nation's capital, the report said.
In November, Los Angeles and San Francisco also showed annual gains, but December's downward movement pushed them into negative territory for the year.
"We ended 2010 with a weak report," S&P Index Committee Chairman David Blitzer said in a statement.
"California is doing better with gains from their low points in Los Angeles, San Diego and San Francisco. At the other end is the Sun Belt -- Las Vegas, Miami, Phoenix and Tampa, (Fla.). All four made new lows in December," he said.
Both the 10-city and 20-city composite indexes are above their spring 2009 lows, but 11 of 20 markets in December hit their lowest levels since home prices peaked in 2006 and 2007, the report said.
Charlotte, N.C.; Portland, Ore.; Tampa, Fla., Atlanta, Chicago, Detroit, Las Vegas, Miami, New York, Phoenix and Seattle all hit lows in December.