“Nowadays, orchestras play virtually every style of jazz music, from classical to avant-garde. Countless bands continue to enthral us with the particular sound of the Big Bands and in Portugal, the growing number of groups with these characteristics shows – despite all the difficulties – the vitality of our musicians.” (Luís Hilário, Hot Clube Portugal). The expression BIG BAND was born from the adaptation of the English language to the ensemble/large instrumental group associated with Jazz music and became popular in the late 1920s, with great evidence from the 1930s onwards. The BIG BANDS deeply marked the golden period of swing in the USA, with names like Fletcher Henderson, Count Basie, Benny Goodman, Duke Ellington, Maynard Ferguson, Dizzy Gillespie or Glenn Miller stand out. This concept has spread to Europe, where the existence of Jazz Orchestras with the same purpose is evident, with orchestras such as the European Jazz Orchestra, WDR Big Band, Fire Orchestra, Matosinhos Jazz Orchestra, LUME, among others. The compositions played by BIG BANDS are subject to elaborate arrangements, previously prepared, written in scores and with a more careful and laborious musical preparation, requiring dedication and commitment from their performers.