For the second straight month, sales rose 0.2 percent, falling short of expectations. Economists had expected a 0.4 percent rise.
On a seasonally adjusted basis, sales rose to $426.6 billion in the month, which is 4.7 percent higher than August 2012.
The bureau said sales excluding automobiles rose 0.1 percent month to month, a 3.3 percent climb from August 2012.
Motor vehicle sales rose 0.9 percent month to month and 10.9 percent from 12 months prior.
In another category that has broad implications, the bureau said sales of building materials and garden supplies dropped 0.9 percent from July to August, data that reflects slowing gains in prices for new residential construction.
Gasoline sales were even from July to August and down 1.5 percent from a year earlier, the bureau said.