Cable customers can see a selection of Channel 4 shows, which now includes some in HD, free of charge for up to seven days post-transmission via the 4oD service.
The deal also gives Virgin Media the option of carrying the new Channel 4 HD linear channel, which will launch in December.
Malcolm Wall, Virgin Media's chief executive of content, said: "We are delighted to be adding Channel 4 content to our growing line up of high definition programming. Virgin Media is at the forefront of technology advances in television and is not only offering its customers higher quality pictures in HD, but also the ability to watch what they want when they want it via the on demand service."
Virgin Media's on-demand library already includes HD assets from FilmFlex, the BBC and History Channel.
Channel 4's head of VOD and channel development Sarah Rose said: "Demand for HD is increasing, and befitting our ambition for viewers to be able to access our programming when they want it and in a format of their choice, it's important for us to be meeting this demand wherever we can. We are delighted that HD versions of some of our shows will be available to Virgin TV on demand users and look forward to increasing the amount of HD programming in our schedule over time."