Biennial Ostrava Days is a three-week long institute, which culminates into a 9-day festival. It is a working environment with a focus on compositions for orchestra. With two resident orchestras - the 95-piece Janáček Philharmonic Orchestra and Ostravská banda (circa 35 musicians) - as well as a score of chamber ensembles, conductors, soloists and 35-piece choir Canticum Ostrava, it is one of the largest events of its kind in the world. It is organized biennially and since its inception in 2001, it has made a significant contribution to the music of today.
Ostrava Days Festival unfolds during the last week of the Institute and includes circa 19 concerts, seven of which are with Janáček Philharmonic Orchestra and Ostravská banda. The programming of the festival is independent of mainstream festival programs and has included major works by Christian Wolff, Alvin Lucier, Petr Kotik, Martin Smolka, Phill Niblock, Elliott Sharp, Bernhard Lang, Rebecca Sauders, Kaija Saariaho, among others. Classics of new music are also often presented. They include works by Morton Feldman, John Cage, Earle Brown, Luigi Nono, Iannis Xenakis, Karlheinz Stockhausen, György Ligeti, Edgard Varèse or Galina Ustwolskaja, among others. The program of the festival also includes substantial number of works by resident-students of the Ostrava Days Institute.