Divorces are more common because they are easier to get. Illinois annulments have stricter requirements than divorce including strict time limits.

The main reason to choose annulment instead of divorce is to avoid court ordered payments. A divorce could force the couple to divide their property. It can also force one spouse to pay maintenance to the other.

The grounds declaring a marriage invalid are specified under Illinois law and the time limits for filing on each of those grounds are:

A petition for invalidity must not be filed to set aside a prohibited marriage because a prohibited marriage is void from the onset. For example, a bigamous marriage - a wedding ceremony with someone who already has a legal spouse - is prohibited; no marriage results, so there's really no marriage to be annulled. However, many lawyers recommend seeking a judicial declaration of invalidity in the case of a prohibited marriage.

Either party may request a declaration of invalidity for a void marriage. In the case of a bigamous marriage, the legal spouse or the State's Attorney may file, and after the death of one of the parties, a child of either party may file within three years of the death of the first party to die.

Children born of a marriage that is declared invalid are still legitimate.

For a legal marriage, the parties must get a license, go through a marriage ceremony, and register the marriage. A flaw or error in the license or registration alone does not invalidate a marriage, but lack of a marriage ceremony does.

A putative spouse is one who goes through a marriage ceremony and proceeds to cohabit with another to whom he or she is not legally married, in the good faith belief that he or she is married" to that person. The putative spouse has the same rights as a legal spouse, including alimony following termination of the spousal status, whether or not the marriage is prohibited. This protects the rights of someone who innocently enters into a void marriage. When the putative spouse finds out the truth - that is, that he or she isn't validly married - his or her status as a putative spouse ends, and the putative spouse can't acquire any further marital rights.

In a bigamous marriage, with one or more putative spouses involved, rights acquired by a putative spouse do not supersede or displace the rights of a legal spouse or those acquired by other putative spouses. The court distributes property, maintenance, and support rights among the claimants as appropriate under the circumstances and in the interests of justice.

The petitioner obtains an Illinois Petition for Annulment form at the county circuit court clerk's office and pays the appropriate fees. The petition is submitted to the county's circuit court clerk office in person. The circuit court clerk's office will then schedule a hearing date after the Illinois Petition for Annulment has been processed.