The president asked for $79.4 billion to fund so-called overseas contingency operations in fiscal 2014, which begins Oct. 1, down from his original $88.5 billion request, a White House aide said. Obama made the request in a letter to Congress.
The U.S. chief executive has said he plans to draw down troops in Afghanistan after 2014 but has not specified by how much.
"The president is still reviewing options from his national security team and has not made a decision about the size of a possible U.S. presence after 2014," National Security Council spokeswoman Caitlin Hayden said.
"The lower request reflects our transitioning role in Afghanistan," she said.
The president is due to announce in the next few weeks how many combat troops the United States will leave in Afghanistan next year, Secretary of State John Kerry said on Tuesday.
The president has set 2014 as the target for withdrawing most of the troops but the decision is a delicate one as sufficient forces must stay behind to train and support Afghan forces and carry out some operations.
U.S. troops first went to Afghanistan after the Sept. 11, 2001, attacks on the United States to root out al Qaeda and its Taliban protectors.