The 4 Legal Grounds for Contesting a Will in Colorado

December 15, 2025 Posted In Trust & Will Contests

When a loved one passes, their Last Will and Testament is supposed to be a final expression of their wishes. But what happens when that document does not seem right? 

In Colorado, a will is presumed to be valid, and challenging it is a significant undertaking. Simply being left out or feeling the distribution is unfair is not a legal basis for a contest. The burden of proof rests squarely on the person challenging the document, which is why working with a Lakewood will contests attorney is critical when clear and convincing evidence is required.

However, Colorado law provides protections. If a will was created under improper circumstances and does not reflect the true, free intent of the testator (the person who made the will), it may be overturned

If you have questions about the validity of a loved one’s will, we invite you to schedule a consultation on our contact us page.

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Key Takeaways for Contesting a Will in Colorado

1. You must have specific legal grounds to contest a will. Simply feeling the distribution is unfair is not enough; you need evidence of issues like lack of mental capacity, undue influence, fraud, or improper signing.
2. The testator’s mental state at the exact time of signing is what matters. A diagnosis like dementia does not automatically invalidate a will if it was signed during a period of lucidity.
3. A no-contest clause is not an absolute bar to a challenge. In Colorado, these clauses are unenforceable if you have probable cause, which is a reasonable, evidence-based belief, to bring the will contest.

Ground 1: Lack of Testamentary Capacity (The Mental State)

One of the most common grounds for a will contest is that the testator lacked the mental capacity to create a valid will, which often raises questions like do I need a will. Capacity is measured at the precise moment the will was signed.

The Legal Threshold for Capacity

The mental standard required to make a will, known as testamentary capacity, is lower than the standard needed to sign a contract. A person does not need to be perfectly sharp. Under Colorado law, they generally only need to understand four basic things:

• The nature of their act (that they are signing a will).
• The extent of their property (a general idea of what they own).
• Who their natural beneficiaries are (their immediate family).
• The distribution they are making (who gets what).

This standard is also called the Cunningham test, based on a landmark Colorado case.

What About Dementia or a Lucid Interval?

A diagnosis of dementia or Alzheimer’s does not automatically invalidate a will. The law recognizes that people with cognitive decline may experience periods of clarity. 

If the will was signed during a lucid interval, where the testator met the four points above, a court may uphold it. Proving a lack of capacity requires substantial evidence, such as medical records, neurologist notes, and testimony from the witnesses and the attorney who drafted the will about the testator’s behavior on the day of signing.

Ground 2: Undue Influence (The Overpowered Will)

This is perhaps the most litigated ground for contesting a will in Colorado today. Undue influence occurs when a person in a position of trust manipulates the testator to such a degree that the will no longer reflects the testator’s true wishes but rather the desires of the influencer.

The core of an undue influence claim is that the testator’s free will was overpowered, often raising concerns about the costs of administering a will when improper conduct affects the estate. This frequently involves a person in a confidential relationship with the testator, such as a caregiver, a new spouse, or a child who has isolated them from the rest of the family.

Red Flags for Undue Influence

Colorado courts look for specific warning signs when evaluating these claims. These red flags do not prove undue influence on their own, but they create a compelling picture when viewed together:

• Drastic Changes: The new will makes a sudden and unexplained departure from previous estate plans.
• Active Procurement: The primary beneficiary was directly involved in arranging for the new will, such as hiring the lawyer or being present during meetings.
• Isolation: The testator was kept away from other family members or longtime friends around the time the will was changed.
• Vulnerability: The testator was physically or emotionally vulnerable due to illness or dependency on the influencer.

A Shift in the Burden of Proof

If the person accused of undue influence was in a fiduciary or confidential relationship with the testator (like holding a Power of Attorney) and was actively involved in procuring the will, the burden of proof may shift. In such cases, the court might require the alleged influencer to prove that the will was, in fact, fair and not a product of their manipulation.

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Ground 3: Fraud, Forgery, and Duress

While less common than capacity or influence claims, these grounds involve intentional acts of deception or coercion.

• Fraud in the Inducement: This happens when the testator is knowingly signing a will but is doing so based on a lie. For example, a son might tell his mother, “Your daughter stole money from you,” causing the mother to write her out of the will. The will was signed intentionally, but the decision was based on deceit.
• Fraud in the Execution: Here, the testator is tricked about the very nature of the document they are signing. They might be told it’s a healthcare directive or a Power of Attorney when it is actually a will.
• Forgery: This is a straightforward claim that the signature on the will is not the testator’s. These cases almost always require the testimony of handwriting experts to compare the signature against known valid samples.
• Duress: This is different from influence. Duress involves threats of physical harm or withholding essential care (like medicine) to force a testator to sign a will. It is coercion in its most direct form.

Ground 4: Improper Execution (Failure of Formalities)

A will is a formal legal document, and it must be signed and witnessed according to specific rules to be valid. If these technical requirements are not met, the will may be invalidated, regardless of the testator’s intent. 

Under Colorado Revised Statutes § 15-11-502, a standard will must be:

1. In writing.
2. Signed by the testator.
3. Either signed by at least two credible witnesses or acknowledged by the testator before a notary public.

Colorado law also recognizes holographic or handwritten wills, but for these to be valid, the signature and material portions of the document must be in the testator’s handwriting.

The Harmless Error Rule

Adding a layer of complexity, Colorado has adopted a harmless error rule, which often leads people to ask should I update my will if a minor technical mistake was made during execution. This means that a judge may still validate the will if there is clear and convincing evidence that the decedent intended for the document to be their will.

Protect Your Inheritance and Your Loved One’s Legacy

Do not let a suspicious or improper document dictate your family’s future. Contesting a will is a difficult procedural battle that involves medical evidence, statutory interpretation, and a clear litigation strategy. It is not something to attempt without seasoned representation.

If you suspect a will was procured through undue influence, fraud, or executed when a loved one lacked capacity, we will help you evaluate your standing and your evidence. To discuss your situation with Colorado Estate Matters, Ltd., please visit our contact us page.

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