Italian Neoclassical architect and painter, best known as the builder of numerous works in Russia during and immediately after the reign of Catherine II the Great. He was named “Grand Architect of all the Russias.”

The son of a painter, Quarenghi studied painting first in Bergamo and then in Rome, where he was taught by Anton Raphael Mengs and Stefano Pozzi. Vincenzo Brenna introduced Quarenghi to architecture. In 1779 Baron Friedrich Grimm secured Quarenghi's invitation to Russia by the empress Catherine II.

Among his first important commissions were the English Palace at Peterhof (1781–89; now at Petrodvorets), since destroyed, and the Hermitage Theatre (begun 1782). These were the first buildings in Russia in the Palladian style. Other early constructions include the Bourse and the State Bank (1789–96), massive but undistinguished edifices.

His other works in St. Petersburg included St. George's Hall in the Winter Palace (1786–95), several bridges on the Neva, and a number of academic structures, including the Academy of Sciences (1785–90), the Catherine Institute (1804–07; now the Saltykov-Shchedrin Library), and the Smolny Institute (1806–08). At the royal residence of Tsarskoye Selo, Quarenghi designed the baths, concert hall, church, the Alexander Palace, and other structures.

Quarenghi designed simple but imposing Neoclassical buildings that have clear and precise designs. His favourite format was a plain rectangular block fronted by an elegant central portico with pillars and pediment. His buildings give the city of St. Petersburg much of its pleasant, stately character.