The protest in the Kadikoy district, on the Asian side of Istanbul, attracted mostly members of leftist groups, police said. There were some 100 foreign protesters from Greece, Britain, The Netherlands, Portugal and Syria.
"We want to throw NATO out of Istanbul," said Dogan Aytac, a Turkish protestor with a flag stuck in his hat that read: "Get out Bush!"
A 20-year-old Greek protestor, Odysseas Maaita, said, "We are here to express our solidarity with the Turkish people, with the people of the Middle East and all others that are under attack, to say that we are against NATO."
The summit is to be held on the European side of the city, across the Bosporus, some 10km from Kadikoy.
Turkey dramatically boosted security before Bush's arrival on Saturday and in preparation for the NATO summit, which begins on Monday.
F-16 warplanes patrolled the skies of Istanbul on Sunday. AWACS early warning planes dispatched by NATO will help monitor a no-fly zone over the city. More than 23,000 police will be on duty during the summit. Turkish commandos are patrolling the Bosporus in rubber boats with mounted machine guns.
More than 23,000 police will be on
duty during the summit
Bush, who will attend the summit along with British Prime Minister Tony Blair, French President Jacques Chirac and others, met with Turkish leaders in Ankara on Sunday morning and flies to Istanbul in the early afternoon.
At the protest, demonstrators chanted "Istanbul will be a grave for NATO."
They carried banners, reading: "Down with American Imperialism," and "Go away Bush!"
Greenpeace activists carried signs against nuclear weapons. Others chanted in English: "Yankees Go Home!"
Thousands of policemen, deployed in back streets, watched the crowds from a distance as a police helicopter hovered above.
In Ankara on Saturday, Turkish police fired tear gas at scores of stone-throwing leftist demonstrators, just hours before Bush arrived in the country. Police said 13 officers were injured by rocks hurled during the rally, the Anatolia news agency reported Sunday.
Four people died in a Istanbul bus
blast on Thursday
On Sunday, police rounded up some 15 leftist demonstrators in downtown Ankara, saying the group was planning to stage a firebombing in the city.
Bush's arrival was preceded by a series of protests and bomb blasts, including one on Thursday that injured three people outside the Ankara hotel where Bush is expected to stay. Another blast that same day on an Istanbul bus killed four people and injured 14.
The bombings has been blamed on leftists.
Kurdish, Muslim and leftist groups are active in the country, and security in Istanbul has been of special concern since November, when four truck bombings blamed on al-Qaida killed more than 60 people.