The crash between a car and a van happened northbound near the Red Cow exit at around half past 10.

The woman, who was the only person in the car at the time, was rushed to James Connolly hospital in Blanchardstown but was pronounced dead a short time later.

A man who was driving the van suffered non life threatening injuries.

The M50 was closed overnight but has since reopened and Gardaí at Ronanstown are appealing for witnesses.