Before the introduction of divorce to Ireland in 1998 the only divorce recognised in Ireland was a divorce granted outside of the State. The only other option to end marriage was by way of a Nullity. A decree of Nullity requires questioning the validity of the marriage from the outset. The basic distinction between a decree of nullity and a divorce is that a nullity declares that the marriage never existed while a divorce sees the marriage being dissolved.

The effect of a Decree of Nullity is that spouses cease to be legally married to one another and so loose their rights as spouses under various associated legislation. For instance, a person who has successfully sought a Decree of Nullity through the Courts will not be entitled to receive any maintenance in respect of him/herself, as he/she was not a spouse at any time of the other. Also, the various succession rights of spouses will be affected by the Decree, as the parties are no longer considered spouses of each other.

The serious consequences of a Decree of Nullity are that spouses are liable to loose many of the rights associated with marriage. Maintenance rights, property rights and succession rights will no longer apply.

The following grounds can be used to obtain used in trying to obtain a decree of nullity:-

- lack of consent

-duress

-mental illness