When a loved one passes away, discovering unexpected changes in a will can raise serious concerns.

Was the document properly signed?
Was the person mentally competent?
Did someone pressure them to change their estate plan?

Under Illinois law, not every will is automatically valid. There are specific legal requirements that must be satisfied. If those requirements are not met, a will may be declared invalid.

At Grant Park Legal Advisors LLC, we represent clients in Chicago and throughout Cook County in contested will and probate litigation matters. Below, we explain the most common reasons a will may be invalid in Illinois.

1. Lack of Testamentary Capacity

One of the most common grounds for invalidating a will is lack of testamentary capacity.

Under Illinois law (755 ILCS 5/4-1), a person creating a will must understand:

• The nature of the document they are signing
• The extent and approximate value of their property
• The natural objects of their bounty (family members and heirs)
• How their property is being distributed

If the person lacked sufficient mental capacity at the time the will was executed — due to dementia, cognitive decline, illness, or impairment — the will may be invalid.

Importantly, capacity is evaluated at the time the will was signed.

2. Undue Influence

Undue influence occurs when someone exerts improper pressure over the person creating the will, causing them to distribute assets in a way that does not reflect their true wishes.

This often arises when:

• A caregiver or relative isolates the testator
• A vulnerable individual becomes dependent on another person
• A sudden and dramatic change in estate plans benefits one individual
• The influencer is present during drafting or execution

Illinois courts closely examine relationships of trust and dependency when evaluating undue influence claims.

3. Fraud

Fraud may invalidate a will if the testator was deceived about:

• The contents of the document
• The identity of beneficiaries
• Material facts affecting their decisions

For example, if someone misrepresents information to persuade the testator to change their will, that may constitute fraud.

Fraud-based claims require strong evidence and are carefully scrutinized by courts.

4. Duress or Coercion

A will must be executed voluntarily.

If a person signs a will because of threats, intimidation, or coercion, the document may be invalid.

Duress can involve:

• Threats of harm
• Financial pressure
• Emotional manipulation
• Isolation combined with intimidation

The court will evaluate whether the person’s free will was overridden.

5. Improper Execution

Illinois law requires strict compliance with statutory formalities.

Generally, a valid Illinois will must:

• Be in writing
• Be signed by the testator
• Be witnessed by at least two credible witnesses
• Be properly attested

If these requirements are not satisfied, the will may be declared invalid.

Technical defects in signing or witnessing can significantly impact enforceability.

6. Revocation

A will may also be invalid if it was revoked before death.

Revocation can occur by:

• Creating a newer valid will
• Physically destroying the prior will
• Executing a formal revocation document

If a newer valid will exists, it typically controls.

What Happens If a Will Is Declared Invalid?

If a court determines a will is invalid, the estate may be distributed:

• According to a prior valid will, or
• Under Illinois intestacy laws if no valid will exists

Illinois intestacy laws determine distribution among spouses, children, and other heirs.

Time Limits for Challenging a Will in Illinois

Illinois imposes a strict deadline for will contests.

A challenge must generally be filed within six months after the will has been admitted to probate.

Failing to act within this period may permanently bar the claim.

Because timing is critical, early legal consultation is important.

How Probate Litigation Works in Chicago

Will contests are handled in probate court — typically in the Circuit Court of Cook County for Chicago estates.

The process may involve:

• Filing a formal petition
• Discovery and document exchange
• Medical record review
• Depositions and witness testimony
• Court hearings or trial

These matters can be legally and emotionally complex.

Why Legal Representation Matters

Contesting a will requires:

• Understanding Illinois probate statutes
• Gathering medical and documentary evidence
• Analyzing fiduciary relationships
• Presenting a clear legal theory

At Grant Park Legal Advisors LLC, we represent heirs, beneficiaries, and interested parties in contested will matters throughout Chicago and Cook County.

Our goal is to protect your rights and pursue a fair resolution.