Cortanze is a comune (municipality) in the Province of Asti in the Italian region Piedmont, located about 30 km east of Turin and about 15 km northwest of Asti. As of 31 December 2004, it had a population of 266 and an area of 4.5 km2. The municipality of Cortanze contains the frazioni (subdivisions, mainly villages and hamlets) Roera and San Rocco. Cortanze borders the following municipalities: Cunico, Montechiaro d’Asti, Piea, Soglio, and Viale.