The trade group said sales of single-family homes, townhomes, condominiums and co-ops rose to a seasonally adjusted annual rate of 4.47 million in July, up from a revised figure for June of 4.37 million.
Sales for the month were 10.4 percent higher than the 4.05 million level of July 2011.
"Mortgage interest rates have been at record lows this year while rents have been rising at faster rates. Combined, these factors are helping to unleash a pent-up demand," said NAR chief economist Lawrence Yun.
Data also shows the median sales price for existing homes rose 9.4 percent from a year earlier, reaching $187,300 in July.
The inventory of homes on the market rose 1.3 percent to 2.4 million, which represents a 6.4-month supply at the current rate of sales, NAR said.
Teacher apologizes for showing sexual image of herself in class
Senate Democrats to pull all-nighter on climate change