The average price of regular unleaded gasoline rose nine-tenths of a cent to $3.669 a gallon from $3.66 a day earlier, according to motorist group AAA and the Oil Price Information Service.
The price increase is the first in more than 40 days since falling from a record high of $4.114 a gallon set July 17.
Gas prices had been following an 18% decline in the price of crude oil - the main ingredient of gas.
Overall, gas prices have fallen off their highs in recent weeks. But prices at the pump are still 33% above the same time last year, when a gallon of gas cost $2.769.
