This quadruple report provides comprehensive insight into the legal situation of unmarried cohabitees in Denmark, Finland, Norway and Sweden. Cohabitees are unmarried couples living together similarly to spouses, but mostly without the same legal security and certainty, as their situation is only in two of four countries regulated in statutory law. Contrary to the intense cooperation that took place between Denmark, Norway and Sweden in the early 1910s preparing new marriage laws, there has been no cooperation at all regarding the legal status of unmarried cohabitees. That makes it an interesting area for comparative research especially.