It was built between 1880 and 1910 to a Gothic Revival design by John Loughborough Pearson on the site of the parish church of St Mary.

The Diocese of Truro was established in December 1876, and its first bishop, Edward White Benson, was consecrated on 25 April 1877 at St Paul's Cathedral.

It was built on the site of the 16th-century parish church of St Mary the Virgin, a building in the Perpendicular style with a spire 128 feet (39 m) tall.

The seats were free and unappropriated, accommodated fewer than 400 people and was extremely hot in summer and cold in winter.

Pearson's design combines the Early English style with certain French characteristics, chiefly spires and rose windows.

Three brasses were described by Edwin Dunkin in 1882: those of Cuthbert Sydnam (1630), Thomas Hasell (1567) and George Fitzpen, rector of the parish.

[12] In 2002 the cathedral embarked on what was hoped to be a fifteen-year project to restore the east end, the west front and the central tower and spire.

The east end restoration repaired stonework and damage to the iron work on the stained glass windows.

Restoration work is being carried out by W. R. Bedford; Stuart Aston, managing director, said that the problem is the Bath Stone used on the more decorative areas of the cathedral, has not stood up well to the salts and sand in the maritime climate of Cornwall.

Both instruments have the standard Willis hallmarks—tierce mixtures on Great and Swell, characterful gedackts on the Choir, and a small but telling pedal division.

Apart from the addition of the electric blower in the 1920s, no major work was done until 1963, when the grandson of the original builder carried out a conservative restoration, at a cost of some £17,000.

Before this time, the organ console was situated high up within the main case of the instrument, necessitating a walk of two or three minutes up a spiral staircase in the north transept.

In 1963, the organ committee decided to keep the original tonal scheme and voicing, and move the console over on to the south side in a new gallery placed above the choir stalls to a design by the architect John Phillips.

The other main organ in the cathedral is a two-manual instrument in St Mary's aisle, the sole remnant of the former parish church.

[25] Four further bells, also cast by Taylor, were installed in 2011: two completing the original ring to twelve, and two smaller ones to give the option of a lighter sound.

[26] In addition there are six bells in the Green Tower, previously in St Mary's Parish Church, of which five form a chiming peal.