Osvaldo Nicolás Ferraro Gutiérrez aka Waldo de los Rios (7 September 1934 - 28 March 1977) was an Argentinean composer, conductor and arranger.
Son of Marta Inés Gutiérrez de Vargas aka Marta De Los Rios
De los Ríos was a native of Buenos Aires who relocated to the USA in 1958 and then Spain in 1962. He is best-remembered for his ability to transform European classical music into pop music. This includes a 1971 update of Mozart's Symphony No. 40. De los Rios' compositions were heard in the 1967 film Pampa Salvaje, for which he received a prestigious award from the Argentine Cinemagraphic Association.
His record Mozart in the Seventies rearranged famous Mozart pieces in a contemporary style, with a large percussion section. Several tracks from it were used as theme tunes to BBC programmes of that era, including the theme to the BBC's coverage of the Horse of the Year show.
He also issued an album "Symphonies for the Seventies" which included Mozart's Symphony no. 40 and other major composers including Dvořák's New World.
He was married to journalist Isabel Pisano who later wrote about part of his life in "El Amado Fantasma" (2002).
De los Ríos committed suicide in 1977.