The Commerce Department said that the trade gap surged 11.2 percent to a record $80.9 billion. Economists polled by Reuters had forecast an $80.5 billion deficit.
Exports tumbled 3.0 percent to $207.6 billion in September. Goods exports plunged 4.7 percent to $142.7 billion. The decline was led by industrial supplies, with crude oil exports decreasing $1.0 billion. Capital goods exports also fell. But consumer goods exports were the highest on record.
Imports rose 0.6 percent to a record $288.5 billion. Goods imports rose 0.8 percent to $240.9 billion, also a record high. Imports of industrial supplies and materials were the highest since April 2014. Capital goods imports set record highs, as did non-petroleum imports and imports of other goods.
Imports are likely to remain high as businesses rebuild depleted inventories.
Trade subtracted from gross domestic product growth in the third quarter, helping to restrain economic growth to a 2 percent annualized rate, the slowest in more than a year. The trade gap has been a drag on GDP growth for five straight quarters.