The Dow Jones Industrial Average closed down more than 500-points at just under 11,400.
Fears about the U.S. economic recovery and a growing debt crisis in Europe get some of the blame.
The Labor Department's jobs report due out tomorrow is expected to show employers added just 85-
thousand jobs in June.
Just before the closing bell, the S&P 500 was also down about 50 points and the Nasdaq had dropped more than 110 points.
All indexes closed down about four-percent.