The N11 in Co Wicklow has been closed between the Beehive and the Tap pubs following a fatal collision at 8.30am.
A 23-year-old man died in the collision between two cars. Three other passengers in the car he was driving were uninjured.
The female driver of the other car was taken to St Vincents hospital where she is being treated for non-life threatening injuries.
The road remains closed while the crash is investigated and diversions are in place. motorists are advised to avoid using this route if possible.