The Church of St. Casimir is an architectural monument in Lviv. The church at different times had different names: St. Catherine, missionary, mercy, St. Casimir. It is located in the central part of the city, on Maxim Krivonos street, 1 (the former Polish names of the street are Archbishopska and Theatinska), near the Church of the Barefoot Carmelites.
The temple was built in 1656-1664 for the monks of the Roman Catholic Reformed Order. A wooden church and a monastery were founded on this site in 1630, which burned down during the assault by the troops of Maxim Krivonos of the Lviv citadel - the High Castle in 1648. In 1783, it was handed over by the Austrian authorities for the organization of a hospital to the nuns of the sisters of mercy, who had their own church nearby.

The church is modest, baroque; a monastic orphanage was attached to it. The style of the church was influenced by the artistic image of Il Gesu. The building is made of stone, single-nave, rectangular in plan, with an elongated apse. From above, the temple is covered with a gable roof and crowned with a signature. The main facade of the Church of St. Casimir is completed with a baroque pediment.
The building is owned by the Lviv Institute of Internal Affairs.