He started his career in the field of contemporary music and jazz, and in the 1950s started his research into the social significance of folk and popular music. He published widely, including L'altra musica (The Other Music; ed.Giunti-Ricordi 1991) and I canti popolari italiani, (Songs of the Peoples of Italy; Mondadori, 1973.) He was known as sponsor and coordinator of numerous projects and festivals to display and preserve Italian music, both traditional and recent. Shortly before his death, he donated his entire private collection (some 700 musical instruments), 6,000 records, 10,000 books, and 1,000 tapes) to the Centro di dialettologia e di etnografia (Center for Dialectology and Ethnography) in Bellinzona, Switzerland.
Marcello Sorce Keller, "En souvenir de Roberto Leydi (1928-2003) – Les origines et l’évolution de l’éthnomusicologie en Italie", Cahiers de musiques traditionnelles, XVII/2004, pp. 297-314; republished as "Un ricordo di Roberto Leydi (1928-2003): un’occasione per riflettere sulle origini dell’etnomusicologia in Italia", Cenobio, LIV(2005), no. 2, pp. 145-162.