The 23-year-old man is currently in a stable condition in University Hospital Waterford (UHW) after being injured in what is being called a street row in Waterford city centre.
The incident on John Street at around 3.30pm.
It's understood that the incident occurred following a dispute between a group of up to five men. The dispute escalated when the young man was approached from behind and allegedly slashed across the back of the head with a knife or blade.
Gardaí and emergency services were at the scene within minutes.
The injured man, who was bleeding profusely, was rushed to UHW for emergency treatment. It's been reported that he is now in a stable condition. His head injury is no longer considered to be life-threatening.
Gardaí have appealed to anyone who witnessed the incident to assist their inquiry. Detectives urged anyone with information to contact Waterford Garda Station on (051) 305300.
