Chester Cathedral is the mother church of the Church of England Diocese of Chester, and is located in the city of Chester, Cheshire, England. The cathedral, formerly St Werburgh's abbey church of a Benedictine monastery, is dedicated to Christ and the Blessed Virgin Mary. Since 1541 it has been the centre of worship, administration, ceremony and music for the city and diocese.

The cathedral is a Grade I listed building, and the heritage site, including the former monastic buildings, lying to the north of the cathedral is also listed Grade I. The cathedral, typical of English cathedrals in having been modified many times, dates from between 1093 and the early 16th century, although the site itself may have been used for Christian worship since Roman times. All the major styles of English medieval architecture, from Norman to Perpendicular are represented in the present building.

The cathedral and monastic buildings were extensively restored during the 19th century amidst some controversy, and a free-standing bell-tower was added in the 20th century. The buildings are a major tourist attraction in Chester, a city of historic, cultural and architectural importance. In addition to holding services for Christian worship, the cathedral is used as a venue for concerts and exhibitions.

The city of Chester was an important Roman stronghold. There may have been a Christian basilica on the site of the present cathedral in the late Roman era, while Chester was controlled by Legio XX Valeria Victrix. Legend holds that the basilica was dedicated to St Paul and St Peter. This is supported by evidence that in Saxon times the dedication of an early chapel on this site was changed from St Peter to St Werburgh. In the 10th century, St Werburgh's remains were brought to Chester, and 907 AD her shrine was placed in the church. It is thought that Æthelfleda turned the church into a college of secular canons, and that it was given a charter by King Edgar in 968. The abbey, as it was then, was restored in 1057 by Leofric, Earl of Mercia and Lady Godiva. This abbey was razed to the ground around 1090, with the secular canons evicted, and no known trace of it remains.

In 1093 a Benedictine monastery was established on the site by Hugh Lupus, Earl of Chester, and the earliest surviving parts of the structure date from that time. The abbey church was not at that time the cathedral of Chester; from 1075 to 1082 the cathedral of the diocese was the nearby church of St John the Baptist, after which the see was transferred to Coventry. In 1538, during the dissolution of the monasteries, the monastery was disbanded and the shrine of St Werburgh was desecrated. In 1541 St Werburgh's abbey became a cathedral of the Church of England by order of Henry VIII. At the same time, the dedication was changed to Christ and the Blessed Virgin. The last abbot of St Werburgh’s Abbey, Thomas Clarke, became the first dean of the new cathedral at the head of a secular chapter.

Although little trace of the 10th century church has been discovered, save possibly some Saxon masonry found during a 1997 excavation of the nave, there is much evidence of the monastery of 1093. This work in the Norman style may be seen in the northwest tower, the north transept and in remaining parts of the monastic buildings. The abbey church, beginning with the Lady Chapel at the eastern end, was extensively rebuilt in Gothic style during the 13th and 14th centuries. At the time of the dissolution of the monasteries, the cloister, the central tower, a new south transept, the large west window and a new entrance porch to the south had just been built in the Perpendicular style, and the southwest tower of the façade had been begun. The west front was given a Tudor entrance, but the tower was never completed.

In 1636 the space beneath the south west tower became a bishop's consistory court. It was furnished as such at that time, and is now a unique survival in England, hearing its last case, that of an attempted suicide of a priest, in the 1930s. Until 1881, the south transept, which is unusually large, also took on a separate function as an independent ecclesiastical entity, the parish church of St Oswald. Although the 17th century saw additions to the furnishings and fittings, there was no further building work for several centuries. By the 19th century, the building was badly in need of restoration. The present homogeneous appearance that the cathedral presents from many exterior angles is largely the work of Victorian restorers, particularly George Gilbert Scott. The 20th century has seen continued maintenance and restoration. In 1973–75 a detached belfry designed by George Pace was erected in the grounds of the cathedral. In 2005 a new Song School was added to the cathedral. During the 2000s, the cathedral library was refurbished and relocated. It was officially reopened in September 2007. The cathedral and the former monastic buildings were designated by English Heritage as Grade I listed buildings on 28 July 1955.