James R. Killian Jr., 83, a past president of the Massachusetts Institute of Technology who served as President Dwight D. Eisenhower's first special assistant for science and technology, died of a heart ailment Jan. 29 at his home in Cambridge, Mass.

He was president of MIT from 1949 to 1959. During the last two of those years, he took leave to hold the dual jobs of special presidential assistant and chairman of the President's Science Advisory Committee. In those posts, he was the first White House science adviser. From 1959 to 1971, he was chairman of the MIT Corp.

Dr. Killian also had chaired a host of important government panels. These posts ranged from the chairmanship of the Foreign Intelligence Advisory Board from 1961 to 1963, to the board chairmanship of the Corporation for Public Broadcasting. He also had been a member of the general advisory board of the U.S. Arms Control and Disarmament Agency from 1969 to 1974.

Before serving the Eisenhower White House, he had gained a reputation as one of the nation's premier educators, as an eloquent spokesman for science, and as a leading administrator. All these traits were put to immediate use after his White House appointment in November 1957.

At that time, the American public seemed to many to be in a confused, angry and nearly hysterical state concerning science and scientists. The nation that had developed the atomic bomb and perfected radar, along the way to emerging as probably the biggest victor of World War II, had just seen the Soviet Union orbit the first Earth satellite, Sputnik I.

It was Dr. Killian's unenviable task to find out and tell the public what had gone wrong, and whether Soviet science had indeed surpassed the West. His voice was an informed one of calm, reason and authority. He pointed out that if America was behind in outer space, it was by a small margin, and that the country was on the right track. While voicing the need for reforms in science education, he also said that the U.S. system was much superior to the Soviet Union's.

He also became an invaluable aide to the president by working to cut red tape and to help resolve interservice military rivalries concerning science. He helped ensure that the space exploration program was accelerated and that what became NASA was under civilian control.

Dr. Killian was a native of Blacksburg, S.C., and a 1926 graduate of MIT, where he earned a bachelor's degree in business and engineering administration. After graduating, he remained at the university as assistant manager of Technology Review, its science and technology policy magazine. He was named managing editor in 1927, and editor three years after that.

In 1939, he became executive assistant to MIT President Karl Taylor Compton. Dr. Killian became executive vice president in 1943, then vice president and member of the MIT Corp. in 1945. In April 1949, he became president of the university, the first graduate of MIT to hold that post.

During those years, Dr. Killian not only had helped administer a large university specializing in science and engineering, but also had helped MIT lend its expertise to the war effort. It was at MIT's radiation laboratory that radar was perfected for American forces.

While continuing to put great emphasis on science and engineering, Dr. Killian also spoke of the need for scientists to receive broader training in the liberal arts. A School of Humanities and Social Studies and a Center of International Studies were established during his tenure.

He also spoke out on the need for funding of science education and for better secondary programs for the intellectually gifted. He said, "Our preoccupation in America with the common man should not let us forget that our advancement depends upon the uncommon man."

During the Truman administration, Dr. Killian was a member of the Presidential Commission on Management, the Communications Policy Board and the Office of Defense Mobilization's science advisory committee. In 1954, he directed a National Security Council task force on military technology. The group recommended the development of the Polaris guided missile submarine and the U-2 spy plane.

Dr. Killian was a member of the board of the Corporation for Public Broadcasting from 1968 to 1975, and its chairman from 1973 to 1974. In 1965, he was chairman of the Carnegie Commission on Educational Television, whose recommendations led Congress to pass the Public Television Act of 1967.

He was the recipient of 39 honorary degrees, as well as numerous government and private awards. He had served on the boards of the Federal Reserve Bank of Boston, the Mitre Corp., Polaroid, IBM and General Motors. He was a past chairman of the Institute for Defense Analyses.

His wife, the former Elizabeth Parks, whom he married in 1929, died in 1986. Survivors include a daughter, Carolyn Staley of Berwyn, Pa.; a son, R. Meredith Killian of Chelmsford, Mass.; a sister, Ruth Nicholls of Wellesley, Mass., and six grandchildren.