San Marcello al Corso is a church in Rome, Italy, devoted to Pope Marcellus I. It is located in via del Corso, the ancient via Lata, connecting Piazza Venezia to Piazza del Popolo.

While the tradition holds that the church was built over the prison of Pope Marcellus I (d. 309), it is known that the Titulus Marcelli was already present in 418, when Pope Boniface I was elected here. The "Septiformis" litany, commanded by Pope Gregory I in 590, saw the men moving from San Marcello.

Pope Adrian I, in the 8th century, built a church on the same place, which is currently under the modern church.

The corpse of Cola di Rienzo, was held in the church for three days after his execution in 1354. On 22 May 1519 a fire destroyed the church. The money collected for its rebuilding was used to bribe the landsknechts, who were pillaging the city during the Sack of Rome (1527). The original plan to rebuild the church was designed by Jacopo Sansovino, who fled the city during the Sack and never returned to finish it. The work was continued by Antonio da Sangallo the Younger, who rebuilt the church, but a Tiber flood damaged it again in 1530. It was only in 1592 that the church was completed, and later Carlo Fontana built the facade.