Frank G. Ruiz, 77, a former musician, orchestra leader and radio host kwho also worked for the Wonder Bread Bakery here for 20 years, died of a respiratory ailment Tuesday at the Washington Hospital Center.

Born and reared in Mazatlan, Mexico, Mr. Ruiz was a professional bass player in his native country. In about 1931, he moved to New York City and formed his own orchestra, which performed on "The Frank Ruiz Spanish Hour," a weekly radio program.

He moved to Washington in about 1939 and formed another musical group, "Ruiz and his Rumba Orchestra." During the 1940s and early 1950s, the orchestra performed regularly on Mr. Ruiz's hour-long weekly radio broadcast, "The Spanish Hour." In the 1940s, it was the featured orchestra at the old 400 Club here.

During this time, Mr. Ruiz also worked as a clerk at the Wonder Bread Bakery, from which he retired in the mid-1960s.

He then played bass for about five years with the Victor Ponti Orchestra.

Until his retirement in 1974, he worked locally as a free-lance musician, specializing in Spanish music.

He was a longtime member of the American Federation of Musicians and was active in the Shrine of the Sacred Heart Catholic Church here.

He wife of 50 years, Frances, died in 1979.

Survivors include a daughter, Maria T. Morales, and a son, Raul, both of Washington; another son, Frank Jr., of Suitland; a stepdaughter, Sara Ramos of Puerto Rico; a stepson, Hannibal Martinez of Hyattsville and 10 grandchildren.