Washington Petition To Invalidate (Annul) Marriage is a legal process whereby a marriage is declared null and void and is treated as if it never existed. This process can be used by a married individual in Washington State who wishes to dissolve their marriage and have it legally annulled. The process requires a petition to be submitted to the court, which must include details about the marriage, such as the date it began, how long it lasted, any children from the marriage, and the grounds for annulment. The grounds for annulment in Washington State include fraud, duress, mental incapacity, or lack of consent. Once the petition is approved and the marriage is legally annulled, the court will issue a decree of annulment. There are two types of Washington Petition to Invalidate (Annul) Marriage: annulment by decree, which is filed in Superior Court, and annulment by declaration, which can be filed in either Superior Court or District Court.