Fontana dei Catecumeni, Public drinking fountain in Piazza della Madonna dei Monti, Rome, Italy.

The Fontana dei Catecumeni is an octagonal travertine basin in Piazza della Madonna dei Monti, designed by Giacomo Della Porta in 1588 and built by Battista Rusconi in 1589. Four alternating coats of arms, two of Sixtus V and two of the city, decorate its sides. It rests on four octagonal steps that level the sloping square, and four masks beneath the upper basin pour water into the lower one.

The fountain was commissioned by Pope Sixtus V from Giacomo Della Porta, who drew the design in 1588; Battista Rusconi built it the following year. It followed the 1587 completion of the Acqua Felice aqueduct, whose secondary branch supplied the Viminale and Quirinale hills. The octagonal basin was set on its four steps in 1595 by Girolamo de Rossi. Innocent XI had it restored in 1680, and the city restored it in 1879-80 and again in 1997.

The name "dei Catecumeni" comes from the nearby Collegio dei Neofiti, also called dei catecumeni, a 1635 palace on via della Madonna dei Monti a short distance from the square. The octagonal basin carries four alternating coats of arms, two of Sixtus V and two of the Comune, so papal and civic authority face each other on the same stone.

The fountain stands in the sloping Piazza della Madonna dei Monti, in front of the church of Santa Maria ai Monti. Its four octagonal steps, set in place by Girolamo de Rossi in 1595, level the ground toward the church and serve as seating. The square was repaved and closed to traffic in 1997, when the fountain was restored.

The upper basin was originally topped by a vase; under Innocent XI, around the end of the 17th century, it was replaced by a second baluster carrying a smaller circular basin from which the water still spouts. Four masks beneath the lower basin pour water into the octagonal travertine pool.