The capacity of T In The Park will rise to 85,000 after organisers were granted a new license.
The new permit will allow 5,000 extra festival-goers on site, provided they are camping tickets.
Revellers will be allowed to camp on the Thursday before the festival begins, which organisers hope will prevent the traffic jams that marred the festival back in 2007.
T In The Park 2009 will take place at Balado, Kinross-shire from 10-12 July with early rumours suggesting that Franz Ferdinand and Glasvegas will perform.
Early bird tickets for the festival have already sold out.