Electrical machinery orders fell 1.6 percent, to $19.6 billion, after rising 2.8 percent in February.
The August gain was led by a 9.2 percent rise in machinery orders, where the increase was broad based.
That report said machinery orders fell 4.1 percent in October from September.
Electrical machinery orders rose 2.6 percent, to $20.8 billion, after a 1.5 percent gain a month earlier.
An agency official said the March figure indicated that the downtrend in machinery orders is coming to an end.
Electrical machinery orders fell 15.5 percent after a 5.4 percent December gain.
Economists expected an increase in machinery orders for August of more than 5 percent.
Electrical machinery orders were up 5 percent after a 7.3 percent rise in November.
It disclosed that machinery orders, an important indicator of investment, fell nearly 12 percent in January from the previous month.
Private machinery orders collapsed in December, down 28% from the previous month.