Last Will and Testament vs. Pre-Nuptial Agreement: Which One Prevails?

Last Will and Testament vs. Pre-Nuptial Agreement: Which One Prevails?

August 11, 2025

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Tanko Law Montana

Simple Answer: It depends on the language of the documents..


Prenuptial/Anti-nuptial Agreements


Generally speaking, a Pre-nuptial Agreement is an agreement that is entered into prior to marriage that delineates each person’s property and how that property is to be handled in the marriage and beyond. In Montana, these agreements are contracts that must be entered into with full disclosure and without coercion.


Prenuptial Agreements and Wills


If the terms of the Prenuptial Agreement conflict with the terms of either spouse's Last Will and Testament, a Montana probate court may choose to uphold the Agreement unless the deceased spouse's beneficiaries can show that the Agreement was created under duress, is unfair, or tended to “encourage” divorce, according to the Legal Information Institute. Montana probate courts tend to rule in favor of a Prenuptial Agreement when it appears that the Agreement was fairly negotiated and entered into with full and fair disclosure of assets and debts.


What If There Is No Will?


A Prenuptial Agreement may be used to distribute the estate if one spouse dies intestate, meaning without a will or estate plan, or if a will was later found to be invalid. Usually, the Montana probate court will apply state law to decide who receives the property left by an intestate person. However, since the Agreement is a contract made while the deceased person was alive that deals with that person's property, the court may use the Agreement to distribute the property. In this situation, the Agreement can over-ride Montana state law even if a will could not.


Specificity Matters.


A Prenuptial Agreement is more likely to take priority over a will in Montana if it contains a few specific clauses. The Agreement should state which law should be applied to interpret it, especially if it was made in a different state than Montana. Otherwise, the law in Montana will be controlled, even if that was not the law the couple had in mind when they made the will. A Prenuptial Agreement may also contain a “sunset clause”- a provision that delineates an expiration date for the Agreement. If that date has passed, the Agreement is no longer binding and the will may govern the distribution of the estate.


For more information, please contact Estate Planning Attorney Brian C. Tanko at Tanko Law Office 406-257-3711, or visit us on our website at www.tankolaw.com and Facebook at www.facebook.com/tankolaw.

Talk to a Montana Estate Planning Attorney

Brian Tanko brings over 20 years of experience as an attorney, CPA, and Certified Fraud Examiner to every estate plan. Schedule a consultation to discuss your situation.

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