A 71-year-old male was assaulted while out walking in Kilkenny City on Saturday evening.
The incident took place at 9pm at Johns Green. The male was hit from behind with an object making contact to the back of his head.
There were a group of youths in the area at the time and one of them had a stick in his possession.
Gardaí have canvassed the area for CCTV footage and are appealing to anyone who witnessed the incident or who has dashcam footage to contact them at Kilkenny Garda Station on (056) 7775000.