A 22-year-old man was attacked at the T in the Park campsite at about 12.45am. The Police are calling for witnesses to come forward.
The 22-year-old male was found by police with multiple stab wounds in the campsite's Yellow Zone in the early hours.
He was treated by medics on the scene before being taken by ambulance to Dundee's Ninewells Hospital, where he was said to be in a serious but stable condition.The victim's parents have been informed and the area where the incident took place has been cordoned off for officers to conduct a forensic examination.
Police are interviewing witnesses at the site in Balado, Kinross-shire, and are hunting two men they believe are responsible.
A spokesman said: "Given the nature of this incident it is likely that both men will have had blood-stained clothing."
The first man is described as being white, in his late teens, around 6ft 1in tall, of skinny build with short dark brown hair. He was wearing a white tracksuit top.
The second man is described as being white, around 5ft 8in tall, of medium build and with short dark brown "mullet-style" hair. He was wearing a red tracksuit top. Can you help identify them?
Witnesses are asked to speak to any police officer on the festival site or contact Tayside Police on 0845 600 5705.
R.E.M. and Amy Winehouse are due to appear today at the festival which attracted more than 80,000 people, with roughly 60,000 camping for the weekend.
The three-day event began on Friday and ends today.
Prior to the stabbing, police said they there had been no reports of serious crime at the festival site, with only seven people taken into custody.