| 1910 | Semirâma (poema tragico / tragedia lirica in 3 atti) · opera · chorus | Confirmed | 140' |
| 1914 | Il tramonto (mezzo & strings) | Confirmed | 15' |
| 1914 | Marie Victoire (opera in 4 atti e 5 quadri) · opera · chorus | Confirmed | 150' |
| 1914 | Sinfonia drammatica | Confirmed | 55' |
| 1916 | Fontane di Roma (Fountains of Rome) | Confirmed | 16' |
| 1917 | Ancient Airs and Dances, Suite No. 1 | Confirmed | 16' |
| 1919 | La boutique fantasque — Concert Suite (after Rossini) | Confirmed | 18' |
| 1919 | La boutique fantasque (arr. from Rossini) | Confirmed | 35' |
| 1920 | Ballata delle gnomidi | Confirmed | 15' |
| 1920 | La pentola magica (The Magic Pot) — azione coreografica in due quadri | Confirmed | 30' |
| 1920 | Le astuzie femminili — balletto (after Cimarosa) | Confirmed | 13' |
| 1920 | Scherzo veneziano (Le astuzie di Colombina) — azione coreografica | Confirmed | 35' |
| 1920 | Sèvres de la vieille France — azione coreografica | Confirmed | 30' |
| 1921 | Concerto gregoriano (violin & orchestra) | Confirmed | 28' |
| 1922 | La bella dormente nel bosco (fiaba musicale in 3 atti) · chorus | Confirmed | 66' |
| 1923 | Ancient Airs and Dances, Suite No. 2 | Confirmed | 19' |
| 1923 | Belfagor (commedia lirica in un prologo, due atti e un epilogo) · opera · chorus | Confirmed | 130' |
| 1924 | Pini di Roma (Pines of Rome) | Confirmed | 22' |
| 1925 | Concerto in modo misolidio (piano & orchestra) | Confirmed | 33' |
| 1925 | Poema autunnale (violin & orchestra) | Confirmed | 17' |
| 1925 | Rossiniana | Confirmed | 25' |
| 1926 | Vetrate di chiesa (Church Windows) | Confirmed | 25' |
| 1927 | Impressioni brasiliane (Brazilian Impressions) | Confirmed | 20' |
| 1927 | La campana sommersa (The Sunken Bell) — opera in 4 atti · opera · chorus | Confirmed | 150' |
| 1927 | Trittico botticelliano | Confirmed | 20' |
| 1928 | Feste romane (Roman Festivals) | Confirmed | 25' |
| 1928 | Gli uccelli (The Birds) | Confirmed | 20' |
| 1930 | Metamorphoseon modi XII | Confirmed | 35' |
| 1931 | Ancient Airs and Dances, Suite No. 3 | Confirmed | 18' |
| 1932 | Belkis, regina di Saba — complete ballet in 7 quadri · chorus | Confirmed | 80' |
| 1932 | Maria egiziaca (mistero in tre episodi) · chorus | Confirmed | 55' |
| 1934 | Belkis, Regina di Saba — Suite | Confirmed | 25' |
| 1934 | La fiamma (melodramma in 3 atti e 4 quadri) · opera · chorus | Confirmed | 130' |
| 1935 | Orfeo (Monteverdi, free realisation by Respighi) — favola in musica in 3 atti · opera · chorus | Confirmed | 100' |
| 1937 | Antiche arie e danze — balletto in 4 quadri (11 brani) | Confirmed | 30' |
| 1937 | Lucrezia (istoria in un atto e tre momenti) | Confirmed | 60' |