The Church of the Savior on Blood is one of the main Russian Orthodox cathedrals of St. Petersburg. The name refers to the blood of the assassinated Alexander II of Russia, and that of the martyred Jesus. Construction began in 1883 on the site of the emperor's assassination (1881), and was completed in 1907.

The church is one of the main tourist attractions of St. Petersburg. It contains over 7000 square metres of mosaics, and a memorial marking the spot where the assassination took place. Architecturally, it is out of place in St. Petersburg. The city's architecture is predominantly Baroque and Neoclassical, but the Savior on Blood harks back to medieval Russian architecture. It intentionally resembles the celebrated St. Basil's Cathedral in Moscow.

The church is prominently situated along the Nevsky Prospekt. The street at that point runs along either side of a canal. The section of street where the assassination took place was enclosed within the walls of the church, and part of the canal filled to allow the street to pass around the building.

Alexander III started construction of the church as a memorial to his father. Work progressed slowly and was finally completed under the reign of Nicholas II. Funding was provided by the Royal family with the support of many private investors.

The Soviet Russian government closed the church in the early 1930s. During the Second World War, it was used as a warehouse for vegetables, leading to the sardonic name of Savior on Potatoes. It was reopened in August 1997, after 27 years of restoration, but has not been resanctified and does not function as a place of worship.