(750 ILCS 5/Pt. III heading)

(750 ILCS 5/301) (from Ch. 40, par. 301) Sec. 301. Declaration of Invalidity - Grounds.) The court shall enter its judgment declaring the invalidity of a marriage (formerly known as annulment) entered into under the following circumstances: (1) a party lacked capacity to consent to the marriage at the time the marriage was solemnized, either because of mental incapacity or infirmity or because of the influence of alcohol, drugs or other incapacitating substances, or a party was induced to enter into a marriage by force or duress or by fraud involving the essentials of marriage; (2) a party lacks the physical capacity to consummate the marriage by sexual intercourse and at the time the marriage was solemnized the other party did not know of the incapacity; (3) a party was aged 16 or 17 years and did not have the consent of his parents or guardian or judicial approval; or (4) the marriage is prohibited. (Source: P.A. 80-923.)

(750 ILCS 5/302) (from Ch. 40, par. 302) Sec. 302. Time of Commencement.) (a) A declaration of invalidity under paragraphs (1) through (3) of Section 301 may be sought by any of the following persons and must be commenced within the times specified: (1) for any of the reasons set forth in paragraph (1) of Section 301, by either party or by the legal representative of the party who lacked capacity to consent, no later than 90 days after the petitioner obtained knowledge of the described condition; (2) for the reason set forth in paragraph (2) of Section 301, by either party, no later than one year after the petitioner obtained knowledge of the described condition; (3) for the reason set forth in paragraph (3) of Section 301, by the underaged party, his parent or guardian, prior to the time the underaged party reaches the age at which he could have married without needing to satisfy the omitted requirement. (b) In no event may a declaration of invalidity of marriage be sought after the death of either party to the marriage under subsections (1), (2) and (3) of Section 301. (c) A declaration of invalidity for the reason set forth in paragraph (4) of Section 301 may be sought by either party, the legal spouse in case of a bigamous marriage, the State's Attorney or a child of either party, at any time not to exceed 3 years following the death of the first party to die. (Source: P.A. 80-923.)

(750 ILCS 5/303) (from Ch. 40, par. 303) Sec. 303. Legitimacy of Children.) Children born or adopted of a marriage declared invalid are the lawful children of the parties. Children whose parents marry after their birth are the lawful children of the parties. (Source: P.A. 94-229, eff. 1-1-06.)

(750 ILCS 5/304) (from Ch. 40, par. 304) Sec. 304. Retroactivity. Unless the court finds, after a consideration of all relevant circumstances, including the effect of a retroactive judgment on third parties, that the interests of justice would be served by making the judgment not retroactive, it shall declare the marriage invalid as of the date of the marriage. The provisions of this Act relating to property rights of the spouses, maintenance, support of children, and allocation of parental responsibilities on dissolution of marriage are applicable to non-retroactive judgments of invalidity of marriage only. (Source: P.A. 99-90, eff. 1-1-16.)

(750 ILCS 5/305) (from Ch. 40, par. 305) Sec. 305. Putative Spouse.) Any person, having gone through a marriage ceremony, who has cohabited with another to whom he is not legally married in the good faith belief that he was married to that person is a putative spouse until knowledge of the fact that he is not legally married terminates his status and prevents acquisition of further rights. A putative spouse acquires the rights conferred upon a legal spouse, including the right to maintenance following termination of his status, whether or not the marriage is prohibited, under Section 212, or declared invalid, under Section 301. If there is a legal spouse or other putative spouse, rights acquired by a putative spouse do not supersede the rights of the legal spouse or those acquired by other putative spouses, but the court shall apportion property, maintenance and support rights among the claimants as appropriate in the circumstances and in the interests of justice. This Section shall not apply to common law marriages contracted in the State after June 30, 1905. (Source: P.A. 80-923.)

(750 ILCS 5/306) (from Ch. 40, par. 306) Sec. 306. Commencement of Action.) Actions for declaration of invalidity of marriage shall be commenced as in other civil cases. (Source: P.A. 80-923.)