The July increase to a seasonally adjusted $462.4 billion lifted inventories 15.1 percent above the July 2010 total.
June's inventory level was revised higher by $200 million to $458.9 billion.
Wholesale sales for June were unchanged month-to-month, holding steady at $396 billion. Sales from the same month a year ago were up 14.4 percent, Commerce said.
The inventory-to-sales ratio -- reflecting how many months it would take a company to deplete its inventory at the current sales pace -- came in at 1.17, slightly higher than June's ratio of 1.16.
A year earlier in July the ratio was also 1.16.
Inventories of durable goods -- items meant to last three or more years -- increased 1 percent after a May-to-June increase of 1.3 percent.
Durable goods sales rose 1.4 percent month-to-month and 11.7 percent from July 2010.