The meeting may give clues on what lies ahead with its massive support for markets.
The Fed's policy decision will come at 2 p.m. ET.
A couple of economic data points for investors to consider will be released in the morning.
The Commerce Department is expected to say that the number of new homes being built in May rose slightly to a seasonally adjusted annual rate of 1.63 million, after falling more than expected in April to 1.569 million.
Permits for future construction are anticipated to edge down to 1.730 million in May from 1.733 million the prior month.
At the same time we’ll get import and export prices for May. Prices of imported goods likely rose 0.8%, slightly ahead of April’s 0.7% rise. Export prices, meantime, are also expected to edge up 0.8% in May, matching the prior month’s gain.
In Europe, London's FTSE added 0.2%, Germany's Dax was off 0.3% and France's CAC gained 0.1%.
In Asia, Japan's Nikkei 225 slipped 0.5%, Hong Kong's Hang Seng declined down 0.7% and China's Shanghai Composite declined 1.1%.
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On Tuesday, the S&P 500 dipped 0.2% to 4,246.59. A day earlier, the index hit an all-time high amid optimism about the economy.
The Dow Jones Industrial Average lost 0.3% to 34,299.33. The Nasdaq composite fell 0.7% to 14,072.86.
Earlier in the day, a report showed inflation on the wholesale level leaped last month by even more than economists expected. Prices for producers were 6.6% higher in May than a year earlier, the highest since 2010 and the latest evidence that inflation is bursting higher across the economy.
The fear is that if higher inflation gets entrenched, the Fed may pull back on the $120 billion in monthly purchases of bonds it's pledged to keep mortgages cheap and longer-term interest rates low, and might raise short-term interest rates off their record low.
Most economists expect the Fed to say again on Wednesday that it sees higher inflation as only temporary, which would allow it to hold steady on its support for markets. But they also say Wednesday afternoon could offer the first sign that the Fed is mulling when to start slowing its purchases of bonds.
Other reports on the economy Tuesday painted a mixed picture. Retail sales fell 1.3% in May from April, slamming into reverse after a 0.9% gain the prior month, for a much steeper drop than economists expected.
In energy trading, benchmark U.S. crude gained 36 cents to $72.48 a barrel in electronic trading on the New York Mercantile Exchange. It gained $1.24 on Tuesday to $72.12 per barrel. Brent crude, the international standard, added 38 cents to $74.34 a barrel.
The Associated Press contributed to this report.