The 1973 horror, directed by William Friedkin, won the most votes in the poll by DVD rental service LoveFilm.
Stanley Kubrick's A Clockwork Orange came in second place.
Other films in the top ten included The Texas Chainsaw Massacre, Requiem For A Dream and Antichrist.
The poll was commissioned to mark the release of The Human Centipede.
According to Yahoo, the editor of LoveFilm Helen Cowley said: "As much as we wince and turn away from what's on screen, every film lover secretly loves a good horror flick.
"This list of disturbing films truly showcases the extreme lengths that filmmakers will go to in order to continually shock audiences, but it's great to also see some classics in there - which arguably changed the way horror films are crafted for today's audiences."