Prepare a Petition for Annulment. The state of Illinois does not provide a standardized form; you must draw up the pleading yourself or have your attorney do so in accordance with the court's guidelines. Court pleadings must follow strict content and style format; otherwise, the clerks will simply return them to you without taking any action. In the petition, you or your attorney must state the grounds for the annulment. If your grounds are that you entered into your marriage under duress, you lacked the mental capacity to enter into the marriage, for example, due to the influence of alcohol or drugs, or you were induced into the marriage by fraud such as your spouse claiming to be pregnant when she was not, the deadline for filing for an annulment is 90 days from the time you become aware of the problem. If you are unable to consummate your marriage due to physical incapacity, you have one year to file. If a parent did not give consent to the marriage of a minor child, the parent can file a Petition for Annulment before the underage spouse reaches the age of 18. There is no deadline for an annulment of a marriage prohibited by law, such as a marriage of immediate family members or spouses of the same sex.
Bring your Petition for Annulment to the county or circuit court holding jurisdiction over your place of residence. The clerk will date-stamp the Petition, enter the document into the court record, and collect a filing fee. Serve a copy of the Petition on your spouse, either through a certified private process server or by a county sheriff's department, which is authorized to serve legal papers on respondents. The court will set a deadline for service, normally 90 days, as well as the time limit for an answer to the Petition.
File a Return of Service with the court clerk. This document provides the date of service of the Petition on your spouse, as certified by the process server. Your spouse has a limited amount of time, in most jurisdictions 20 or 30 days, to file the Answer to the Petition for Annulment. The Answer should set out any grounds your spouse may assert against the annulment, which must be considered and decided upon by the court. After the Answer is filed, the court clerk will set a date for the hearing on your Petition.
Attend the court hearing on your Petition. You and your spouse must attend the hearing. Bring evidence and witnesses to support your Petition; answer any questions put to you by the judge. The court will normally render its decision at the conclusion of the hearing, although the judge may hold the case open and the decision pending is any further evidence and/or testimony is needed.
Receive the Declaration of Invalidity of Marriage signed by the judge and entered into the public record by the clerk.