The church has a Baroque main façade (begun in 1606, with the upper part finished in 1961), preceded by a large staircase completed in 1607. The sculptures decorating the three orders of the façade were executed by local sculptors in the 1960s. Other exterior features include the Gothic portal of St. Michael, on the northern façade, and the southern portico of the Apostles, from the 14th century. The latter originally featured sculptures of the Twelve Apostles, executed by Antoni Claperós in the 1460s, which have mostly been lost, aside from two depicting St. Peter and St. Paul, now in the church's chapter house.
The church has two bell towers. The oldest one, named after Charlemagne, is the surviving one of the two originally flanking the first Romanesque church (the other ceased to exist in the 14th century). Begun in the early 11th century, it has a square plan with six levels separated by friezes with Lombard bands and double mullioned windows. The new bell tower, begun in 1590