In the event of death, estate tax must be paid on the inheritance that is paid to the heirs.
The spouse does not have to pay estate tax on inheritance.
Closely related heirs (children, grandchildren, parents, unmarried cohabitants, etc.) must pay 15 % in estate tax, while non-closely related heirs must pay a total of 36.25 % in estate tax.
However, there is a minimum deduction, so that no estate tax is paid on the first DKK 272,900 (2015 figures).
If you are unmarried and cohabiting, and you want to avoid the survivor having to pay estate tax, you can avoid this by getting married.