The most prominent 18th-century architect of Italy, he practised a sober classicising academic Late Baroque style that made an easy transition to Neoclassicism.

At Ancona in 1732, he devised the vast Lazaretto, a pentagonal building covering more than 20,000 square meters, built to protect the military defensive authorities from the risk of contagious diseases potentially reaching the town with the ships.

In Rome, Vanvitelli stabilized the dome of St. Peter's Basilica when it developed cracks and found time to paint frescos in a chapel at Sant Cecilia in Trastevere.

Built of many precious marbles and other costly stones, as well as gilt bronze, it was held to be the most expensive chapel in Europe up to that time.

[citation needed] His engineering talents were exercised as well: for Caserta, he devised the great aqueduct system that brought water to run the cascades and fountains.