In June 1919 he began to form the Pau Casals Orchestra with Enric Casals as first violinist, Enric Ainaud as joint first violinist and Bonaventura Dini as first cellist. On 13 October 1920 the Pau Casals Orchestra made its debut at the Palau de la Music Catalana.
During the following sixteen years the orchestra was led by the best conductors of the time, including Ernest Ansemet, Adrian Boult, Arbós, Fritz Busch, Emil Cooper, Alfred Cortot, Vincent d’Indy, Manuel de Falla, Pierre Monteux, Frank Schalk, Richard Strauss, Igor Stravinsky, Donald Francis Tovey, Felix Weingartner and Eugene Ysaÿe. Outstanding soloists who habitually played with the orchestra included pianists (Cortot, Horszowski, Blai Net), violinists (Ysaÿe, Thibaud, Kreisler, Jelly d’Arany, Mathieu Crickboom, Enric Casals), cellists (Diran Alexanaian, Horace Britt, Gaspar Cassadó, Bonaventura Dini, Maurice Eisenberg, Pierre Fournier, Raya Garbusova) and other international artistes, such as the harpist Wanda Landowska. The orchestra performed until the outbreak of the Spanish Civil War in 1936.