Home prices rose 0.9 percent month-to-month in both the 10-city index and the 20-city index S&P/Case-Shiller tracks.
In 20 major markets, only Seattle bucked the trend with prices dropping 0.1 percent in the month.
On an annual basis, the prices in the 10-city index rose 1.3 percent, while prices in the 20-city index rose 2 percent, the report said. For 18 of the 20 cities, the annual price gains were improved August compared with July.
Annual returns for Dallas were unchanged, while the annual rate in Chicago was lower at minus 1.6 percent compared with minus 1 percent in July.
Two other cities besides Chicago posted negative annual returns. Atlanta's annual return came to minus 6.1 percent. In New York, it was minus 2.3 percent.
"Phoenix continues to lead the home price recovery. It recorded its fourth consecutive month of double-digit
positive annual returns with a [plus] 18.8 percent rate for August. Atlanta posted a minus 6.1 percent annual rate; however, this is significantly better than the nine consecutive months of double-digit declines it posted from October 2011 through June 2012," said David Blitzer, chairman of the Index Committee at S&P Indexes.
"The sustained good news in home prices over the past five months makes us optimistic for continued recovery in the housing market," he said.
Besides Phoenix, strong annual gains were posted by Detroit (up 7.6 percent), Minneapolis (up 7.4 percent), Miami (up 6.7 percent) and San Francisco (up 5.3 percent).