San Giovanni Decollato alle Case Rotte, Medieval church building in Porta Nuova district, Milan, Italy.

San Giovanni Decollato alle Case Rotte was a church in Milan, first built around 1390 and enlarged in 1420, with a choir redone by Pellegrino Tibaldi and later heavy remodelling by Francesco Maria Richini. Its interior had an octagonal plan inscribed in an ellipse, richly decorated with mainly 18th-century frescoes and stuccoes. The facade had two orders: a lower atrium of three arches on two pairs of paired columns, and an upper level topped by a plain pediment.

The first church on the site dates to around 1390, built on the ruins of the Torriani quarter destroyed after 1311 and known as the case rotte. It was enlarged in 1420, received a new choir by Pellegrino Tibaldi and was heavily remodelled by Francesco Maria Richini. Closed for worship in 1874, it served as the municipal archive for thirty years before demolition in late 1907 for Luca Beltrami's Banca Commerciale Italiana.

The name "alle Case Rotte" refers to the ruined houses of the Torriani, destroyed after 1311 and never rebuilt by decree of the Commune. The church kept this name, and its fourteenth-century fresco of the Madonna del latte, called the "Madonna dei Torriani", was moved at the end of the nineteenth century to the Cappella delle ballerine in the nearby church of San Fedele.

The church no longer stands: it was demolished at the end of 1907 for the Banca Commerciale Italiana building facing today's Piazza della Scala. What survives is its facade, moved in 1924 by architect Paolo Mezzanotte to the right flank of Santa Maria Segreta in via Ariosto, where it now joins the two churches.

The facade was re-erected in 1924 on the right flank of Santa Maria Segreta in via Ariosto, joining the two churches through new buildings that also housed a parish hall and the Cinema Ariosto. The operation was handled by the architects Paolo Mezzanotte and the construction firms Samb, Carlo Magnaghi and Antonio Bassanini.