The victim was transferred to hospital in Dublin for treatment of his injuries.
Gardaí are renewing their appeal for witnesses to a serious assault at Electric Picnic.
A man in his 30s has been left with non-life threatening but serious injuries following the attack on the opening night of the festival in Stradbally.
It happened between 10 o'clock and midnight on Friday, the 2nd in the Today FM Sound Garden.
The assault is alleged to have happened during the last song of DJ Jamie Maguire's set.
The victim was taken to Tullamore Hospital and was later transferred to St James’s Hospital, Dublin
Gardaí are urging anyone who may have witnessed the incident or has camera footage to come forward.
Any person with information can contact Portlaoise Garda Station on 057 867 4100, the Garda Confidential Line on 1800 66 111 or any Garda Station.