The arrests were made on Saturday evening after scuffles broke out between hundreds of anti-war demonstrators and the riot police.
Demonstrators condemned the alliance’s involvement in the Afghan war and other military operations.
Tensions have been high between police and demonstrators in two days of protest rallies leading up to the summit, which is to be held in the US away from the capital Washington for the first time.
Leaders of the 28 members of the North Atlantic Treaty Organization (NATO) and 22 allied countries are expected to attend this year’s summit to discuss several issues, especially the war in Afghanistan.
Chicago police have been preparing for the event for nearly a year, and officers from police departments as far away as Philadelphia and Milwaukee are expected to assist local forces in security measures and crowd control.
While the Saturday protest marches were reportedly largely spontaneous, the largest planned rally against the NATO alliance is set for Sunday, when the meeting opens.
PG/PKH/MA