The Baptistery Hall is a circular space with a unique morphology, centered around the basin for adult baptisms, which gives the room its name. The space is vaulted, with the central vault supported by eight columns, and 14 open niches arranged along the sides for the exhibition.

This room is liturgical, designed for the administration of the Holy Baptism for adults, but also serves as an exhibition space, where two important themes are presented: church servants who belong to the laity and altar servants who make up the priesthood.

The theme of the priesthood, including both lower and higher clergy, was represented until 2023 in the lateral niches through liturgical vestments and symbols specific to each rank and service. Since then, temporary exhibitions on various themes have been organized in this room.

As a general feature, this space provides a special ambiance through the combination of architectural themes inspired by Byzantine style and the mural painting done by the artist Grigore Popescu.

The Baptistery Hall is located in the plan of the Metropolitan Ensemble beneath the historical monument known as the "Fântâna lui Mihail de Hodocin" (Fountain of Mihail de Hodocin), and it communicates with the outside through a skylight placed at the center of the vault.