Ingeborg Keij and Carel Harmsen Paper presented at the European Population Conference in Helsinki, Finland, 7 - 9 June 2001.The number of cohabiting couples in the Netherlands has strongly increased in the 1990s. Because cohabiting couples run a higher risk of breaking up than married couples, this trend has attributed to the increase in the number of singles. How strong this increase is, also depends on how soon formerly cohabiting persons find a new partner. The chance of ever entering into a new consensual union again depends, among other things, on sex, age and the presence of children. The vast majority of persons who experience a separation are cohabiting again within four years. The increase in the number of singles as a result of separation is for the major part made up of persons who live alone for just a relatively short period.