Secretary-General Jaap de Hoop Scheffer has met privately with Bush a handful of times, but never before at the president's getaway in central Texas. The invitation was meant to be a special treat, an offer of extended personal time with Bush.
Afghanistan's surging violence, NATO's role in Kosovo and U.S. plans for a missile defense system in Europe all were likely to be on Monday's agenda.
On Sunday, a relaxed Bush and first lady Laura Bush greeted de Hoop Scheffer and his wife, Jeannine, who arrived by helicopter.
The president, in blue jeans and cowboy boots, then climbed into his extended-cab pickup truck and drove the couples down the road — men in the front seat, women in the back seat.
In Afghanistan, more than 1,600 people have been killed in insurgency-related violence this year, according to U.S., NATO and Afghan figures. The mounting civilian death toll has fueled distrust of international forces and U.S.-backed President Hamid Karzai.
"It's a very high priority for us, just on a humanitarian level," White House spokesman Tony Fratto said Sunday. "It's a high priority for us on a hearts-and-minds level: We don't want to see any erosion of support from the civilian population."
Fratto said the blame lies with Taliban militants who use civilians as shields. "This is a clear, express tactic of the enemy to put civilians in harm's way," he said.
The role of the 26-nation alliance in the war in Afghanistan remains a sensitive matter.
The Bush administration is urging some European allies to provide more troops to fight Taliban forces in southern Afghanistan and to lift restrictions on how and where soldiers can fight.
Politicians in the United States, Canada, Britain and other nations with troops in the south have been annoyed by the reluctance of some European allies to commit extra soldiers to the roughly 37,000-strong NATO force — in particular to be deployed to the Taliban's heartland.
Monday's discussions also were to address the status of Kosovo, a poor region under U.N. administration since 1999.
The U.S. backs a U.N. resolution to ratify the province's independence from Serbia, but that plan is opposed by Russia, a permanent member of the Security Council with veto power.
Moscow has opposed successive enlargements of NATO into Eastern Europe. NATO's likely expansion into the Balkans does not please Russia, but the Kremlin has shown even more concern about the prospect that neighbors Ukraine and Georgia may be brought into the alliance.
Russia is also critical of U.S. plans to install radar and interceptors in Eastern Europe as part of a missile defense program, another source of growing tension between the countries.