Frédéric Chopin's Fantaisie-Impromptu in C-sharp minor, Op. posth. 66, is a solo piano composition. It was composed in 1834 and published posthumously in 1855 although he had instructed that none of his unpublished manuscripts should be published. Despite negative comments, the Fantaisie-Impromptu is one of Chopin's most frequently performed and popular compositions.

Date of composition 1835 (1834-1835)
Premiered 1855 in Paris, France
First published 1855
Type Impromptu
Tonality C-sharp Minor
Catalogue Op. 66
Instruments Piano
In listings Famous Works
Autotranslations beta Frédéric Chopin: Fantaisie-impromptu en do dièse mineur, Op. 66
Fryderyk Chopin: Fantaisie-impromptu in do diesis minore, Op. 66
Frédéric Chopin: Fantaisie-impromptu cis-moll, Op. 66