Busto Arsizio's 2021 population is now estimated at 657,698. In 1950, the population of Busto Arsizio was 333,332. Busto Arsizio has grown by 3,440 since 2015, which represents a 0.53% annual change. These population estimates and projections come from the latest revision of the UN World Urbanization Prospects. These estimates represent the Urban agglomeration of Busto Arsizio, which typically includes Busto Arsizio's population in addition to adjacent suburban areas.