Film4OD, which officially launched today, has more than 500 films available for 48-hour rental online. Prices ranging from 50p to £3.99.
Titles include The Girl With The Dragon Tattoo and Shutter Island, along with Film4-backed movies such as Four Lions and Slumdog Millionaire.
The service, which will go head to head with the on-demand movie offerings of Blinkbox and LoveFilm, will operate in addition to the existing 4OD catch-up TV platform.
Channel 4 also plans to use Film4OD to amplify its broadcast seasons, such as the forthcoming 'partners in crime' season.
Last month, Channel 4 announced that Film4's film financing budget would be increased by 50% from next year to £15 million per annum.