'''Filem hilang''' adalahialah [[filem fiturcetera]] atau [[filem pendek]] yang tidak diketahui lagi keberadaannya di arkib studio, koleksi peribadi, atau arkib publikawam seperti [[Library of Congress|''Library of Congress'']].<ref>At least one copy of every American film is required to be deposited and catalogued at the Library of Congress for copyright reasons. Although U.S. copyright law required copies to be deposited at the time of copyright registration, the Librarian of Congress was not required to retain those copies. "Under the provisions of the act of March 4, 1909, authority is granted for the return to the claimant of copyright of such copyright deposits as are not required by the Library." [http://www.copyright.gov/reports/annual/archive/ar-1913.pdf Report of the Register of Copyrights for the Fiscal Year 1912–1913], Library of Congress, 1913, p. 141.</ref> Bilangan [[filem senyap]] Amerika Syarikat yang hilang lebih banyak daripada yang bertahan dan daridaripada seluruh [[filem suara]] Amerika Syarikat tahun 1927 hingga 1950, separuhnya diperkirakandipanggarkan menghilanghilang daripada peredaran.<ref>{{cite news |author=[[Dave Kehr]] |coauthors= |title=Film Riches, Cleaned Up for Posterity |url=http://www.nytimes.com/2010/10/15/movies/15restore.html?_r=1&scp=1&sq=film%20preservation&st=cse |quote=It’s bad enough, to cite a common estimate, that 90 percent of all American silent films and 50 percent of American sound films made before 1950 appear to have vanished forever. |work=[[New York Times]] |date=October 14, 2010 |accessdate=2010-10-15 }}</ref> Frasa "filmfilem hilang" juga boleh digunakan secara harafiah manakala rakaman [[adegan gagal]], ialah filem fiturcetera yang belum disunting atau versi alternatifnya yang diketahui telah dibuat namun tidak diketahui kewujudannya. Salinan filem hilang kadang-kadang ditemukan kembali. Filem yang belum ditemukan utuhdalam keaadaan lengkap disebutdigelar filem separuh hilang (''partially lost film''). MisalnyaContohnya, filem ''[[Sherlock Holmes (filem 1922)|Sherlock Holmes]]'' (1922) akhirnya ditemukan namun sebagiansebahagian rekamannyarakamannya masih dinyatakan hilang.
