Two men were airlifted to Galway University Hospital after an incident on Inis Mór this afternoon.
A 47-year-old man is in a critical but stable condition after he sustained stab wounds in the incident.
A second man, aged 67 and who is a resident of Inis Mór, is said to have non life-threatening injuries.
Gardaí say an altercation broke out on a public road in Kilronan at around 1pm.
The men were brought to hospital in Galway on separate flights, with one of them accompanied by a Garda.
Gardaí in Kilronan are investigating the incident and no arrests have been made.