Soedjatmoko, a prominent Indonesian intellectual and former diplomat, died of cardiac arrest yesterday at Muhammadiyeh Islamic University in Jogjakarta, in Central Java, where he was lecturing. He was 67 years old and lived in Jakarta, the nation's capital.

A widely known Southeast Asian social scientist, Mr. Soedjatmoko served as alternate permanent representative to the United Nations from 1947 to 1951 and as Ambassador to the United States from 1968 to 1971.

Born into a family of nobility on Sumatra, he attended medical college in Jakarta before attending the Littauer Graduate School of Public Administration at Harvard.

As Indonesia gained independence from the Dutch after World War II, Mr. Soedjatmoko served as an official in the new country's Ministry of Information. From 1956 to 1959 he was a member of the Indonesian Constitutent Assembly, when he also was associate editor of of Pedoman, a daily newspaper, and director of the publishing house of P. T. Pembangunan.

In 1980 Mr. Soedjatmoko was named rector of the United Nations University in Tokyo, a post he held until his retirement in 1987. Since then he continued to teach and lecture aroung the world.

He was the author of several books, ''The Re-Emergence of Southeast Asia: An Indonesian Perspective'' (1969), and 'The Primacy of Freedom in Development'' (1986).

In 1973 Mr. Soedjatmoko became the first member of a developing country to become a trustee of the Ford Foundation.

Survivors include his wife, the former Ratmini Gandasubrata; three daughters, Nana and Isna, both of Jakarta, and Galuh , of Philadelphia; two sisters and a brother.

Soedjatmoko (Camera Associates, 1968)