|Directed by||Bill Morrison|
|Written by||Bill Morrison|
|Produced by||Bill Morrison|
|Edited by||Bill Morrison|
|Music by||Michael Gordon|
|Distributed by||Icarus Films|
Decasia is a 2002 American collage film by Bill Morrison, featuring an original score by Michael Gordon. In 2013, Decasia was included in the annual selection of 25 motion pictures for preservation in the United States National Film Registry by the Library of Congress as being "culturally, historically, or aesthetically significant". 
The film is a meditation on old, decaying silent films, featuring segments of earlier movies re-edited and integrated into a new narrative. Critic Glen Kenny described Decasia as an "abstract narrative about mortality in all of its manifestations."
It begins and ends with scenes of a dervish and is bookended with old footage showing how film is processed. Nothing was done to accelerate the decomposition of the actual film prints, some of which were copied from the University of South Carolina's Moving Image Research Collections  as well as deteriorating film footage that Morrison found at the Library of Congress. 
The film's musical soundtrack features several detuned pianos and an orchestra playing out of phase with itself, adding to the fractured and decomposing nature of the film.
Various films that were incorporated into Decasia have been positively identified: J. Farrell MacDonald's The Last Egyptian (1914), written, produced, and based on the novel by L. Frank Baum; William S. Hart's Truthful Tulliver (1917); Norman Dawn's A Tokyo Siren (1920); John H. Collins's The Man Who Could Not Sleep (1915); Eddie Lyons's Peace and Quiet (1921) and Phillips Smalley's The Mind Cure (1912). Various Fox Movietone newsreel footage were also used. 
In 2013, Decasia was selected for preservation by the National Film Registry. It was the first film from the 21st century to be selected. Decasia was included in the September 2014 box set release of Bill Morrison's collected works, from Icarus Films.
- "Complete National Film Registry Listing". Library of Congress. Retrieved 2020-06-04.
- "Cinema with the Right Stuff Marks 2013 National Film Registry". Library of Congress. Retrieved 2020-06-04.
- Beauty In The Broken: Filmmaker Bill Morrison’s Visions of Decay Celebrated in New Box Set|TV/Streaming|Roger Ebert
- Morrison, Bill. "Portrait of Decay: Bill Morrison on Decasia". Retrieved 5 May 2013.
- "Library of Congress announces 2013 National Film Registry selections". The Washington Post (Press release). December 18, 2013. Retrieved December 18, 2013.
- Brown University Library Search
- "Amazon.com: Bill Morrison: Collected Works (1996 - 2013): Vijay Iyer, Johann Johannsson, Michael Gordon, Bill Frisell, Bill Morrison: Movies & TV".