The loonie rose 0.47 of a cent to 101.68 cents US, and the greenback moved lower following the Fed announcement.
The Federal Reserve said in a statement that the economy is slowly improving, but chairman Ben Bernanke told a press conference that he would still consider another round of bond buying to help the economy.
The Fed's statement followed a two-day policy meeting and did not mention new steps to help the economy. The U.S. dollar fell against the euro after Bernanke said additional bond purchases remain "very much on the table."
The Fed has launched two rounds of bond purchases, most recently in August 2010, to lower long-term interest rates and make stocks more attractive to investors.
Meanwhile, U.S. durable goods orders fell by the largest amount in three years last month, mostly because demand for commercial aircraft plummeted. The Commerce Department said orders for durable goods dropped 4.2 per cent in March, the steepest fall since January 2009.
In commodities, the May crude contract on the New York Mercantile Exchange ended up 57 cents to US$104.12 a barrel. Gold bullion prices backed down $1.50 to close at US$1,642.30 an ounce. Copper prices were down less than a cent to US$3.69 a pound.