Despite increasingly bloody clashes with a resurgent Taliban Islamist militia, the NATO chief said in an interview with CNN television the situation was "looking quite good."
"We are making a lot of progress. The international community should I think better know the meaning of the word 'patience,'" he said.
Saying he was "cautiously optimistic" after a recent visit to Afghanistan, Scheffer said the country was headed in a positive direction after years of poverty and war.
"We do see millions of children in school. We see the literacy rate going up. We see health care going up. Over 80 percent of Afghans have access to health care.
"In 2001, do not forget, Afghanistan was in the Middle Ages," he said.
"If you look between '01 and '08, there is a lot of progress, although the challenges, of course, are formidable."
US-led forces invaded Afghanistan in 2001 to topple the Taliban regime allied with Al-Qaeda.
The NATO chief spoke after holding talks on Afghanistan and other issues Friday with President George W. Bush, who has urged alliance members to contribute more troops for combat in southern Afghanistan.
Scheffer said he expected more troop contributions for Afghanistan at an April summit in Bucharest.
"You will see at the summit in Bucharest ... without any doubt even more of the forces coming in," he said, without providing further details.
The Bush administration has been pressing its allies to commit more troops to Afghanistan, but many countries face fierce opposition at home and will only allow their forces to be deployed for training missions -- not for combat in the south.