Emerson Foote, the outspoken co-founder of the Foote, Cone & Belding advertising agency and former chairman of McCann-Erickson Inc., died on Sunday at a convalescent home in Carmel, N.Y. He was 85 years old and a longtime Carmel resident.

His family said he had been stricken with appendicitis and died of postoperative complications.

The two agencies he led rank among the biggest in the world today, and Mr. Foote, tall and distinguished-looking, stood as one of the giants of the industry. He became known to the general public for his acerbic views of tobacco advertising, which eventually prompted him to leave advertising. He was a former chain-smoker and was a director of the American Cancer Society.

Mr. Foote resigned as chairman of McCann-Erickson in 1964, saying he was opposed to handling cigarette accounts. He was then a member of President Lyndon B. Johnson's Commission on Heart Disease, Cancer and Stroke and endorsed the Surgeon General's report that linked cigarette smoking and lung cancer.

He ridiculed protestations that billions spent on promotions had nothing to do with people taking up the habit. "I am always amused," Mr. Foote said, "by the suggestion that advertising, a function that has been shown to increase consumption of virtually every other product, somehow miraculously fails to work for tobacco products."