"Structural productivity continues to grow at a firm pace, and rebuilding activity following the hurricanes should boost real GDP growth for a while," Greenspan said in prepared testimony to the congressional Joint Economic Committee.
"More uncertainty, however, surrounds the outlook for inflation," he said.
The Fed chief also warned the United States needs to boost its supplies of natural gas, though he said they seemed adequate for the moment. "However, a colder-than-average winter would stress this market, and prices will likely remain vulnerable to spikes until the spring," he said.
The 79-year-old Greenspan steps down as chairman of the Federal Reserve at the end of next January, when he will have completed nearly 18-1/2 years as head of the US central bank.
That meant his appearance before the JEC - one of dozens over the decades - almost certainly was his final one as Fed chief and was expected to produce a round of accolades.
Greenspan was in charge of the nation's monetary policy while the longest economic expansion in history was recorded in the 1990s but has taken criticism from some lawmakers for his opaque methods of determining monetary-policy.
President George W. Bush has nominated Ben Bernanke, chairman of the White House's Council of Economic Advisers and a former Fed governor, to succeed Greenspan.
The Senate Banking Committee is expected to hold a hearing on Bernanke's nomination sometime this month, though it remains unclear whether a final Senate vote will come this year or early in 2006.
On Tuesday, Fed policy-makers raised short-term US interest rates for a 12th straight time, bringing the bellwether federal funds rate to 4 percent. They cited concern about the impact of rising energy prices on potential inflation.