The jobless rate shifted on the loss of of 247,000 jobs, about 100,000 less than economists predicted.
For July, economists had forecast a jump in unemployment to 9.6 percent. The surprise decline gave markets a strong boost.
In early afternoon trading, the Dow Jones industrial average gained 172.76 points, 1.87 percent, to 9,429.02. The S&P 500 gained 20.84 points, 2.09 percent, to 1,017.92. The Nasdaq index added 37.35 points, 1.89 percent, to 2,010.51.
The benchmark 10-year Treasury fell 26/32 to yield 3.86 percent.
The euro fell to $1.419 from Thursday's $1.4357. Against the yen, the dollar rose to 97.64 yen from Thursday's 95.37 yen.
In Japan, the Nikkei 225 index added 24 points, 0.23 percent, to 10,412.09.
The FTSE 100 index in Britain roes 0.87 percent, 41.03 points, to 4,731.56.
Copyright 2009 by United Press International.