Santa Maria delle Carceri is a basilica church in Prato
. It is considered one of the earliest, most notable examples of use of Greek cross plan in Renaissance architecture.
The church has four equal-size arms surmounted by a small dome. The external covering is typically bichrome as in many other Prato's buildings, using white and green marble. The lower fraction shows a framed decoration which originally was to be reproduced in the upper area, finishing with a tympanum (this can be seen only in one arm).
The bell tower was realized in 1777-1780 by Francesco Valentini.
The interior has a solemn Renaissance atmosphere, with the four arms starting from the cubical central hall, surmounted by the semi-spherical dome. All corners are marked by fake columns with precious capitals whose entablatures underline the vault.
The arms are decorated by four stained-glass windows designed by Domenico Ghirlandaio (1491). The entablature has a frieze with festoons and coats of arms in majolica from Andrea della Robbia's workshop; Della Robbia was also author of the tondos with Evangelists (1491), in the pendiments of the dome. The latter has a parapet creating an enlarging prospectical effect.
The high altar, designed by Sangallo after that in the Roman Pantheon, is in white marble. The altarpiece is the fresco of the miracle after which the basilica was erected, portraying the Madonna with Child between Sts. Leonard and Stephen (1330–1340).
The presbytery's arms ends with a parapet by Bernardo Buontalenti (1588), flanked by two stone altars (1575).
In the sacristy (fresco of Madonna of Humility, 1420) are some rooms of the ancient jail.