Registration does not necessarily guarantee getting a ticket
Tickets for 2010's Glastonbury festival have gone on sale to music fans who registered with organisers by Friday.
Next year will be the 40th anniversary of the festival and its organiser Michael Eavis has said "expectations are really high".
Fans were able to buy tickets from 0900 BST on Sunday. The registration system, which does not guarantee a ticket, was set up in 2007 to stamp out touting.
Last year fans were able to extend their registration for three years.
A spokesman for the event said the system was a "good, open scheme".
The ticketing system has been a success because "we know all tickets are going to festival-goers", he added.
If anyone is uncertain whether their previous registration is still valid, they are able to check online.
Customers can also participate in the Glastonbury deposit scheme, which allows the buyer to pay a £50 deposit which reserves them a ticket. The final balance can be paid at a later date.
Meanwhile, it has been revealed that Michael Eavis is planning to extend the current four-year licence to 2011.
It is expected that in 2012 the event will not take place to allow the Somerset site to recover.