The rates averaged 4.8 percent, Freddie Mac said.
A week ago, 30-year, fixed-rate mortgages averaged 4.82 percent. A year ago, the average rate was 6.03 percent.
At 4.48 percent, the 15-year, fixed-rate average was unchanged from the previous week, maintaining a record low that dates back to when Freddie Mac first began tracking the weekly figure in 1991.
A year ago, 15-year fixed-rate mortgages averaged 5.62 percent, Freddie Mac said.
"The housing market is showing further signs of possible improvement. House prices rose for the second consecutive month in February, the first back-to-back increase since April 2007," said Frank Nothaft, Freddie Mac vice president and chief economist.