However, many of those purchases involved properties that were subject to foreclosures or short sales, indicating the housing market is far from recovered.
The survey by San Diego-based DataQuick also showed the median sales price in the region fell nearly 3 percent last month from December to $326,000 less than half the peak price of $665,000 reached in 2007 but up from the low of $290,000 recorded in 2009.
A total of 5,479 new and existing homes were sold in the nine-county area, according to DataQuick. The figure was down nearly 27 percent from December but marked a 10.3-percent improvement over January 2011.
The December-to-January drop was normal for the season, while the January-to-January jump showed real improvement, DataQuick said.
The year-over-year increase in January marked the seventh annual jump in a row,the firm said.
Home sales were buoyed by "lower prices, ultra-low mortgage rates, a modestly improved economy and a record level of investor purchases," DataQuick said in a statement.
The lower median price in January was "a reflection of how skewed the market has become toward distressed, lower-cost properties," DataQuick President John Walsh said in the statement. "The higher-end sales have slowed in recent months as many struggle to qualify for loans and others just sit tight."
Distressed property sales the combination of foreclosure and short sales made up more than half of all sales of existing homes. Absentee buyers, who mostly are investors, bought more than a quarter of all homes sold, DataQuick reported