Police said the peak time for crime was on the Saturday of the annual event
Revellers attending this year's Reading Festival have been told to leave their valuables at home after 477 crimes were reported to the police last year.
Thames Valley Police said the figure had slightly increased from 2007 and the Saturday of the event, from 28-30 August, was the peak time for crime.
It also suggested items like cameras could be kept safe in on-site lockers.
The warning comes after the festival was allowed to increase its capacity by 6,500 over the next two years.
Last month, Reading Borough councillors backed organisers' plans to boost this year's capacity of 78,500 ticketholders and 4,999 guests to 82,000 next year and 85,000 from 2011.
This year's festival will feature Arctic Monkeys.