According to European Spatial Planning Observation Network, in 2007 the Naples polycentric metropolitan area had a population of 3,714,000.

[3] More recent evaluations have put the population of the urban agglomeration encompassing Naples at between 3,700,000 and 5,000,000.

The Naples metropolitan area includes the whole metropolitan city of Naples, 35 municipalities in province of Caserta, 10 municipalities in province of Avellino and 34 municipalities in province of Salerno, in all 171 municipalities, Naples metropolitan area - SVIMEZ[unreliable source?]

the most important of these by population are Salerno, Giugliano in Campania, Torre del Greco, Pozzuoli, Casoria e Caserta, as shows the next table.

In reality the metro area is much bigger, but political agreements were made that left it as is currently, and the real estimated population is about 6.8 million.