Industrial production rose 0.6% in December as unusually cold weather helped energy utilities offset a small drop in manufacturing.
The mixed picture from the report by the Federal Reserve shows that economic recovery remains uncertain, as consumers and businesses did not spend enough to spur the production of more factory goods.
It was the sixth straight monthly gain and was in line with economists' expectations.
Electric and gas utilities increased production by 5.9% and mines by 0.2% . Manufacturers produced 0.1% less than in November.
Construction and consumer durable goods posted losses of 2.0% and 0.9%, respectively, while paper products output fell 0.9%.
Still, industrial production for the fourth quarter as a whole increased at an annual rate of 7.0%, reflecting the economy's swing toward growth. The economy grew at an annual 2.2% in the third quarter, and was expected to continue growing through the end of 2009.