The spouse who files the divorce petition is called the plaintiff or petitioner; the other spouse is the defendant or respondent. Illinois does not have a uniform set of domestic relations forms. At a minimum, however, the filer must file a Petition for Dissolution of Marriage, which is a written request for a divorce . Filing in Cook County, specifically, requires the following forms, in addition to the Petition for Dissolution of Marriage: > Domestic Relations Cover Sheet > Four copies of Petition for Dissolution of Marriage > Four copies of the Summons > Affidavit of Service (unless the defendant waives the notice requirement), and > Certificate of Dissolution. If the parties have minor children, the petitioner must also file: > Joint Parenting Agreement > Visitation Form, which is attached as an exhibit to the Joint Parenting Agreement), and > Uniform Order of Support (in cases involving child support).

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The action begins when the petitioner files the divorce papers with the clerk of court. A filing fee must also be paid, which will vary by county, and most jurisdictions do not accept debit cards or personal checks, so it is best to take cash or a certified check.

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Illinois law permits the petitioner to "serve" the other spouse by private process server, sheriff's service, or publication. Service means delivering to the respondent copies of the documents filed in the case. Sheriff's service is the preferred method of service in most Illinois counties. Once the sheriff has delivered the papers, the petitioner receives a proof of service document, which he or she files with the court.

In the case of a missing spouse, Illinois permits the petitioner to publish notification of the divorce in a local newspaper. Service by publication can cost several hundred dollars, however, so it's best to exhaust all efforts to track down an address before resorting to this option.

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An increasing number of Illinois counties require the petitioner and the respondent to file a Financial Disclosure Statement. The form, which requires each party to list out his or her assets and debts, streamlines the process of dividing marital property.

The couples must decide if they will file for divorce together or if one will file alone. Joint filing makes the dissolution easier. For an uncontested divorce, the spouses live apart for at least six months and irreconcilable differences have caused the irretrievable breakdown of the marriage, and the spouses both waive the two-year waiting period.

In many cases the couple can qualify for a Simplified Divorce, which is a much quicker and simpler method of divorcing. In order to divorce this way, the couples must:

Parties need special forms for a simplified divorce or for a divorce with minor children. Some of the forms include:

When spouses settle before their case goes to trial, Illinois requires submission of the agreement and all related documents at what is called a "prove up" hearing. During the hearing, the petitioner must be prepared to answer the judge's questions about the division of the marital property and provide any documentation.

The more unresolved issues, the more the parties disagree, the longer the case takes. Normally it takes approximately one month to have the paper work completed and to obtain a final court date. If the case goes to trial, it can take much longer, up to one year or more.

In the case of a no-fault action based on irreconcilable differences, the waiting period is two years, however if both parties agree, they can waive that two-year period so that the Divorce Finalization Waiting Period is only 6 months.