The service, which is the topic of a major advertising campaign by the channel, follows rivals BBC and ITV in providing an on-demand service over the internet.
The success of the BBC's iPlayer has demonstrated the potential of the internet as a viewing platform, and Five are keen to tap into the market.
Easy to use
"Most viewers understand that you can now get your favourite TV online which allowed us to create a fun, accessible spot that reflects Demand Five's easy-to-use service," said Dom Sykes, the Five on-air brand director.
Five's most popular shows, House, the various CSIs and Grey's Anatomy are all paid for rentals - costing 99p per episode - which could well put many potential users off.
Secondly, the shows use Microsoft's Windows Media Player, which will be deeply unpopular by the anti DRM crusaders.
But Five's focus has now clearly moved to the digital realm, which can only be a good thing for viewers who want more control over their television consumption
"The launch of Demand Five represents the first stage of our digital redevelopment programme. We plan to make a significant step change in the digital space over the coming months," added Five's Head of Digital Media Jonathan Lewis.