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Contesting a Will in Illinois Based on Lack of Capacity


Illinois law recognizes that any testator (the person who executed the will) must have sufficient mental capacity to complete his or her will (also known as “testamentary capacity”). Sometimes the testator will execute a will shortly before their death or during a time when they are suffering from a serious illness and they lack the ability to think coherently and understand the consequences of the will they are signing. Any will signed while the testator is in such a state may be challenged based on a claim that the testator lacked the necessary mental capacity to execute the will. If you discover that your loved one left behind a will which you believe was executed at a time when they lack the required mental capacity to do so, you should consult with a qualified estate litigation attorney immediately to discuss the process of contesting a will in Illinois.

Mental capacity necessary to execute a will in Illinois

A testator’s alleged lack of mental capacity to draft a will is by far the most common grounds for challenging a will. In order to prove that a testator lacked the required testamentary capacity, a will contest claimant must prove that at the time the testator signed the will the testator lacked sufficient mental ability to:

(a)   know and remember the natural objects of his or her bounty;

(b)   comprehend the kind and character of his or her property; and

(c)   make a disposition of his or her property according to some plan formed in the testator’s mind.

The natural objects of the testator’s bounty are usually considered to be the children and close family; however, this group also included “those who have some natural claim upon his benevolence, affection or consideration.” Therefore, the natural objects of a testator’s bounty are not limited to heirs at law. It is important to note that, a testator is merely required to have the capacity to know or recall the natural objects of his or her bounty; the testator’s ability to actually do so is irrelevant.  

An insane delusion may also be a basis to overturn a will. Lack of mental capacity may be the appropriate finding if it can be shown that a testator had an insane delusion pertaining to (a) the natural objects of his or her bounty, (b) the kind and character of his or her property, or (c) the ability to make a disposition of his or her property according to some plan formed in his or her mind; Under Illinois law, lack of capacity exists when the testator knows the objects of his or her bounty but suffers from mental delusions regarding those objects, and the mental delusion must affect the testamentary distribution of the testator’s property


A claim based upon a testator’s lack of capacity as a highly fact specific claim, and every case is unique. If you believe that you were excluded from a will which was executed by a testator who lack the testamentary capacity to do so and would like to discuss your rights and options in challenging a will or making a claim against a decedent’s estate, you need to consult with a qualified estate litigation attorney. The experienced Chicago estate attorneys at Hays Firm LLC have helped many individuals through the process of challenging the will of a loved one and ensuring that their loved one’s true wishes were carried out. Please feel free to contact us anytime to discuss how we can help.