The American Petroleum Institute said the September average for oil imports was 4.4 percent lower than during the same month last year.
The United States is consuming more of its own oil because of domestic production gains, officials said.
The U.S. Energy Department said it expects crude oil production to increase from an average 7.5 million barrels per day in 2013 to 8.5 million bpd next year.
The API report said September oil production was around 7.8 million bpd, its highest level for the month in 25 years.
Petroleum deliveries, a measure of demand, increased by 2.7 percent from September 2012 to average approximately 18.6 million bpd, the API said.
"Demand for petroleum products remains consistent with a gradually improving economy," API Chief Economist John Felmy said in a statement Friday.