The foundation of St. Ouen's Abbey has been variously credited, among others, to Clothair I and to St. Clothilda, but evidence is scanty. It was dedicated at first to St. Peter when the body of St. Ouen, Archbishop of Rouen (d. 678), was buried there; the name of St. Peter and St. Ouen became common and finally St. Ouen only. The history of the abbey, on record from the 1000, is unremarkable; a list of abbots is in Gallia Christiana XI, 140. In 1660 the monastery was united to the Congregation of St. Maur, and when suppressed, in 1794, the community numbered twenty-four. The abbey building itself was vacated by the time of the French Revolution and was subsequently occupied by the Town Hall of Rouen.
The church measures 137m long under 33m high vaults. The central crossing is surmounted by an unusual lantern-style tower similar to that at Ely Cathedral in England. The well-preserved stained glass is predominantly from the 14th century, featuring jewel tones among panels of clear and frosted white glass, and leading to a brighter interior than is usual with Gothic churches. The hitherto unfinished façade was completed between 1846 and 1851.
The basilica contains a large four-manual pipe organ built in 1890 by Aristide Cavaillé-Coll. This instrument is considered to be one of the most important organs in France, and is notable for its unusually powerful 32' Contre Bombarde. The organ stands unaltered and thus is one of the few of the master's works to speak with its original voice.