FedEx's quarterly sales rose 8% to $9.2 billion, above the $9.08 billion that analysts were expecting.
"Outside of the United States, the economy is generally solid," Chief Executive Fred Smith said in a statement.
The Memphis, Tennessee-based company said it expected full-year earnings per share of $6.70 to $7.10, down from its outlook of $7 to $7.40 given in June. Analysts had forecast $7.19.
"As a result of this weaker than anticipated economic environment, particularly its impact on the less-than-truckload freight market, we have reduced our earnings forecast by 4% for the full year," Chief Financial Officer Alan Graf said in a statement.
Less-than-truckload companies consolidate smaller loads into a single truck. The U.S. trucking market has seen weak freight volumes over the past year and faces a tough pricing environment as companies compete for business.
Like its main rival, Atlanta-based United Parcel Service , FedEx is seen as a bellwether of U.S. economic activity.
"Going forward we'll have to see whether the recent interest rate cut [of 50 basis points by the U.S. Federal Reserve] will provide some economic impetus," AMBS Investment Council's Meyers said.
FedEx said it expected second-quarter earnings per share of $1.60 to $1.75. Analysts had forecast $1.95.
For the first quarter, the company said revenue at its core FedEx Express delivery unit rose 4 percent to $5.89 billion. Revenue rose 14% to $1.62 billion at the FedEx Ground delivery unit and jumped 22% to $1.23 billion at FedEx Freight.
The company said regional less-than-truckload shipments at FedEx Freight declined slightly due to slowing U.S. economic growth.
FedEx also announced that it was placing its struggling FedEx Kinko's unit in a new division called FedEx Services with its supply chain services operations. FedEx Services revenue declined slightly to $525 million from $527 million.
In premarket trading, FedEx shares were down 1.7% at $105.72.