Built in 1791 by Cardinal Gianfrancesco Albani, it was restored in 1998. The octagonal plan is a symbol of resurrection. The baptismal font, carved by Francesco Saverio Moschetti of Monte Giorgio, has three doors and symbolizes the Holy Trinity. In the main mirror, Saint John the Baptist is represented in bas-relief in the act of baptizing the Savior.
Inside the source, there is the copper water tank, with the Albani coat of arms.
On the walls, four lunettes tell the story of original sin, next to the painting of the pelican, an allegorical symbol referring to the Eucharist, the Deer, the Ostrich, the Lion and the Elephant symbolize the four cardinal virtues: Prudence, Justice, Strength and Temperance.