Yoneo Sakai, 78, a Washington correspondent for Japanese newspapers since 1947, died of Parkinson's disease Tuesday at the Wisconsin Avenue Nursing Home.

After coming to Washington, he worked for the Japan Broadcasting System, then was bureau chief of the Tokyo Shimbun until the early 1960s. Since then he had contributed articles to the Sankei Shimbun.

Mr. Sakai was a member of the White House Correspondents Association, the Foreign Correspondents Association, the Overseas Writers Club, and the National Press Club.

He was born in Japan and came to this country in the early 1920s. He lived in Los Angeles where he worked as a reporter for the Asahi Shimbun and also wrote poetry and novels.

He covered the Spanish Civil War for Japanese publications.

Mr. Sakai remained in the United States during World War II. During this time he taught Japanese language courses at the Naval Language School in Boulder, Colo., then served in the Office of Strategic Services.

His awards included the Vaughn Award for distinguished writing, and the Order of the Sacred Treasure, Third Class, awarded in 1971 by the emperor of Japan for creative writing, journalism, and contribution to Japanese-American understanding .

He is survived by his wife, Ruby, of the home in Washington, and a daughter, Ruri, of Great Falls, Va.

The family suggests that expressions of sympathy be in the form of contributions to the United Parkinson Foundation or the Japan-America Society.