From the Huffington Post:
John McCain, who has harshly criticized the idea of sitting down with dictators without pre-conditions, appears to have done just that. In 1985, McCain traveled to Chile for a friendly meeting with Chile's military ruler, General Augusto Pinochet, one of the world's most notorious violators of human rights credited with killing more than 3,000 civilians and jailing tens of thousands of others.
The private meeting between McCain and dictator Pinochet has gone previously un-reported anywhere. According to a declassified U.S. Embassy cable secured by The Huffington Post, McCain described the meeting with Pinochet "as friendly and at times warm, but noted that Pinochet does seem obsessed with the threat of communism." McCain, a member of the House Foreign Affairs Committee at the time, made no public or private statements critical of the dictatorship, nor did he meet with members of the democratic opposition in Chile, as far as could be determined from a thorough check of U.S. and Chilean newspaper records and interviews with top opposition leaders.
UPDATE: The McCain campaign issued this response: "There is a huge difference between a junior Congressman meeting a dictator and a President holding unconditional summit meetings with dictators. As the cable describing the meeting recounts, Congressman McCain said meeting with Pinochet was like talking to the head of the John Birch Society. John McCain was a key Republican supporter of Chile's transition to democracy and led on numerous legislative initiatives, including securing U.S. funding for the plebiscite which ended Pinochet's rule."