"Six Degrees of Separation" by John Guare was chosen Monday as best play of the 1990-91 theater season by the New York Drama Critics' Circle.

"Our Country's Good" by Timberlake Wertenbaker was picked as best foreign play, and "The Will Rogers Follies," a Ziegfeld-like extravaganza directed by Tommy Tune, won best musical.A special citation was awarded to actress Eileen Atkins for her portrayal of Virginia Woolf in the one-woman show, "A Room of One's Own."

"Six Degrees of Separation," the story of a con artist who dupes several wealthy New Yorkers, easily won on a first ballot. Other plays receiving votes were "Lost in Yonkers" and "La Bete."

The voting was more fractured for foreign play, which was settled in a second, weighted ballot. "The Sum of Us," "Absent Friends," "Shadowlands" and "A Room of One's Own" also received votes.

Although Wertenbaker is an American citizen, she has lived much of her life in Great Britain. "Our Country's Good" was commissioned by the Royal Court Theater in London and received its premiere there in 1988. The play, the story of a group of English convicts in Australia, later had a commercial run in London's West End.

The critics were equally divided in their voting for best musical, which also went to a second ballot. Among the other choices were "The Secret Garden," "Assassins," "Miss Saigon" and "Falsettoland."

The following are members of the New York Drama Critics' Circle:

Clive Barnes and Jerry Tallmer of The New York Post; John Beaufort, The Christian Science Monitor; Michael Feingold, The Village Voice; William Henry III, Time; Howard Kissel, Don Nelsen and Douglas Watt, the New York Daily News; Mimi Kramer and Edith Oliver, The New Yorker; Jack Kroll, Newsweek; Michael Kuchwara, The Associated Press; Jacques le Sourd, Gannett Newspapers; Julius Novick, The New York Observer; William Raidy, the New-house group; Frank Rich and Mel Gussow, The New York Times (non-voting members); John Simon, New York; Linda Winer and Jan Stuart, Newsday; Edwin Wilson and Melanie Kirkpatrick, The Wall Street Journal.