Ivrea was developed in the 20th century as a testing ground for Olivetti, manufacturer of typewriters, mechanical calculators and office computers.
Unesco described the city as “a model social project” expressing “a modern vision of the relationship between industrial production and architecture”.
Unesco's World Heritage Committee made the announcement at its meeting in Bahrain.
A much older historical site was also added to Unesco's Heritage list on Sunday. The remarkably well-preserved remains of the Caliphate city of Medina Azahara, a medieval Arab Muslim town near the Spanish city of Cordoba, was also rewarded.
The 10th-century Moorish site provides “in-depth knowledge of the now vanished Western Islamic civilisation of Al-Andalus, at the height of its splendour,” Unesco said.
On Saturday the Unesco heritage committee added six other sites to its list, including Inuit hunting grounds in Greenland, ancient Korean mountain Buddhist temples, pre-Islamic sites in Iran, and Mumbai's Art Deco buildings.