The Mater Misericordiae University Hospital, commonly known as the Mater, is a teaching hospital, on Eccles Street in Phibsborough, Dublin, Ireland. It is managed by Ireland East Hospital Group.

The hospital was founded as an initiative of Catherine McAuley of the Sisters of Mercy and was officially opened by Daniel Murray, Archbishop of Dublin, on 24 September 1861. Mater misericordiae means "Mother of Mercy" in Latin, a title of the Virgin Mary and alludes to its founders, the Sisters of Mercy. Electric light, a major step in the improvement of endoscopy, was first used by Sir Francis Cruise, to allow cystoscopy, hysteroscopy and sigmoidoscopy as well as the examination of the nasal (and later thoracic) cavities at the hospital in 1865. It became the first hospital in Ireland to remain open 24 hours a day when it dealt with a cholera epidemic in 1886.

In 2003, the National Pulmonary Hypertension Unit, the leading centre for the treatment of pulmonary hypertension in Ireland, was established at the hospital and, in 2008, the hospital became the first public hospital in Ireland to offer percutaneous aortic valve replacement.

The hospital, which is a teaching hospital for the University College Dublin, has 997 beds, along with 206 Day Beds and 15 Operating Theatres. It contains a negative-pressure ventilation ward which houses the National Bio-Terrorism Unit, and is the National Centre in Ireland for various services. The newly-established Rock Wing will also include a 24-bed trauma ward, helping the hospital to become one of Ireland's two Major Trauma Centres.

• Mary McGivney (1865– ) Royal Red Cross, Matron from 1892–1920. She trained at The London Hospital, Whitechapel, London under Eva Luckes between 1888–1889. McGivney also completed three month's maternity training at Endell Street Women's Hospital, London.

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