It is located on Piazza Benedetto Cairoli, 117 just off the corner of Via Arenula and Via dei Falegnami, a few blocks south of the church of Sant'Andrea della Valle.

The attribute ai Catinari refers to the presence, at the time of its construction, of the many makers of wooden basins (Italian catini) who worked in the area.

It is one of at least three Roman churches dedicated to him (including San Carlo al Corso and San Carlo alle Quattro Fontane) and one of a number of great 17th century preaching churches built by Counter-Reformation orders in the Centro Storico (the others being The Gesù and Sant'Ignazio of the Jesuits, Sant'Andrea della Valle of the Theatines, and the Chiesa Nuova of the Oratorians).

The pendentives of the cupola are frescoed with the Cardinal Virtues (1627–30) by Domenichino who designed the stucco decoration in the dome and probably the other main vaults.

Directly behind the high altar is the oil painting of S. Carlo carrying the Holy Nail in Procession during the Plague by Pietro da Cortona.

The view upwards is through an oculus surrounded by angels in the centre of a dark shallow dome, to a rectangular light-filled room above illuminated by windows which are not visible from below.

[4] The third chapel was designed by Paolo Maruscelli with frescoes of the Persian Martyrdoms (1641) by Giovan Francesco Romanelli and lunettes by Giacinto Gimignani.