The Commerce Department said Thursday inventories rose 0.4 percent after increasing 0.5 percent in December.
Economists polled by Reuters had forecast inventories increasing 0.4 percent in January.
Inventories are a key component of gross domestic product changes.
That was the largest gain since last July and followed a 0.6 percent rise in December.
Businesses accumulated a massive amount of stock in the second half of the year, some of which ended up piling up in warehouses. As a result, they are expected to order fewer goods, which economists say will undercut first-quarter growth.
Inventories added only 0.1 percentage point to the fourth-quarter's 2.4 percent annualized growth rate.
Business sales fell 0.9 percent in January, the largest drop since March last year. Sales had slipped 0.1 percent in December. Some of the weakness in sales could be weather- related.
At January's sales pace, it would take 1.32 months for businesses to clear shelves, up from 1.30 months in December. It was the highest inventory-to-sales ratio since October 2009.