Addressing a gathering at Columbia University's business school, Buffett said, "The financial panic is behind us. Our economy was sputtering, still is sputtering some."
79-year-old, Buffet said there is greater opportunity for investemnt inside the United States than outside adding that economy is far larger than any other.
He appeared at Columbia with Microsoft Corp founder Bill Gates, the world's richest person and a Buffett friend and bridge partner.
Bill Gates said other sectors might also boost the economy over the long term, including information technology, energy and medicine.
According to preliminary government data that released last month showed the US economy expanded in the third quarter, the first three-month period of growth since the second quarter of 2008.