Flatus lifir, later repainted as flatus lifir enn, is a series of wall art on a concrete wall located at the base of Esja besides the Reykjavík-Borgarnes portion of Route 1.

The original graffiti is believed to have been created in the 1980s but its creator is unknown. In 2017 Guðmundur Oddur Magnússon claimed that the original graffiti was created by the artist Róska in the 1970s.

The meaning of the artwork is also unknown as the original graffiti, flatus lifir, does not have a meaning in Icelandic, although the later addition of the suffix enn changed the meaning of the graffiti to 'flatus still lives'. It has been suggested that flatus is in fact the latin for fart, or that it is a corruption of the Icelandic term for Pthirus pubis.

In October 2021, a new version of the wall art was created by Edda Karólína Ævarsdóttir. Her reinterpretation of flatus lifir enn was sponsored by the Húsasmiðjan brand.