The chapel in the end of the right transept is dedicated to Sts. Cosmas and Damian, two martyred 3rd century medical doctors who were patron saints of the Medici family. From 1667 it was the chapel of the family of the Florentine Senator Pietro Nerli (died in 1669), whose tomb and coat-of-arms are in the center of the floor outside of the chapel. Cardinal Francesco Nerli (d. 1670) is also buried here.

The side walls here have two memorials with portrait busts. The one on the right is for Ottaviano Acciaiuoli (d.1659) by Ercole Ferrata, and the other to Mons Ottavio Corsini (d. 1641) by Alessandro Algardi.