Around the inside the Baptistery, is a circle of eight pillars dating from 1163, with capitals carved in human and animal forms by Guidetto at the end of the 12th century. Above these, is the women’s gallery, divided by archivolted pilasters. The vaulted ceiling of the Baptisteryhas a simple plaster finish.
At the centre of this building, on a dais of three steps, is the octagonal baptismal font, made by Guido Bigarelli da Como in 1246. The base is in polychrome marble inlay and the walls are made of marble panels decorated with geometric and rose inlays. Similar decoration can be seen on the altar, behind which is the barrier of the presbytery.
The pulpit, carved by Nicola Pisano in 1259-1260, is placed near the south door. Hexagonal in shape, it rests on seven pillars rising from lions and human forms. The panels, separated by small columns, are carved with stories from the Life of Jesus.