Seregno's 2025 population is now estimated at 638,979. In 1950, the population of Seregno was 260,184. Seregno has grown by 2,875 in the last year, which represents a 0.45% 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 Seregno, which typically includes Seregno's population in addition to adjacent suburban areas.