Montana Power of Attorney Laws: Durable, Medical, and Financial POA (2026)

Montana adopted the Uniform Power of Attorney Act, codified at Mont. Code Ann. sections 72-31-301 through 72-31-367. Under this framework, a financial power of attorney is durable by default, meaning it continues in effect even if the principal later becomes incapacitated, unless the document expressly states otherwise. Execution requires the principal's signature; notarization before a notary public creates a presumption that the signature is genuine. Health care decision-making authority requires a separate document governed by the Montana Rights of the Terminally Ill Act, Mont. Code Ann. sections 50-9-101 through 50-9-111.

What a Power of Attorney Does in Montana

A power of attorney is a written document in which a principal grants an agent, also called an attorney-in-fact, authority to act on the principal's behalf in financial, legal, or other specified matters. The agent can manage bank accounts, pay bills, handle real estate, file taxes, enter contracts, or perform other tasks within the scope of authority the principal grants.

Montana law recognizes several functional types. A general financial POA covers a broad range of financial and legal matters. A limited or special POA covers a single transaction or a defined category of acts. A durable POA survives the principal's incapacity. A springing POA takes effect only upon a future event, such as the principal becoming incapacitated. All financial POAs fall under Mont. Code Ann. Part 3 of Title 72, Chapter 31 when executed under Montana law.

An agent is a fiduciary. The agent must act in the principal's best interest, keep records of all financial transactions, avoid conflicts of interest, and refrain from using the principal's assets for personal gain unless the document specifically permits it. A POA ends at the principal's death; once the principal dies, the personal representative of the estate takes over and the agent's authority ceases entirely.

Durable Power of Attorney in Montana

Under Mont. Code Ann. 72-31-304, a power of attorney created under Montana's Uniform Power of Attorney Act is durable unless it expressly provides that it is terminated by the incapacity of the principal. Montana's default rule favors durability.

This default has real-world significance. A principal who creates a general financial POA without any language about incapacity will automatically have a durable instrument, one that continues to operate if the principal later develops dementia or suffers a serious accident. A principal who wants a non-durable POA must include express language stating that the authority ends if the principal becomes incapacitated.

Mont. Code Ann. 72-31-302 defines "durable" as "not terminated by the principal's incapacity" and defines "incapacity" as the inability to manage property or business affairs because the person has an impairment in the ability to receive and evaluate information or make or communicate decisions, even with technological assistance, or because the person is missing or outside the United States and unable to return.

A principal may also create a springing POA under Mont. Code Ann. 72-31-309, which becomes effective only upon a specified future date or event. If effectiveness depends on the principal's incapacity, a physician or other authorized professional must certify that incapacity has occurred before the agent can act.

How to Create a Valid Montana Power of Attorney

Signing and Notarization

Mont. Code Ann. 72-31-305 sets out the execution requirements for a financial POA. The document must be signed by the principal, or signed in the principal's conscious presence by another individual directed by the principal to sign the principal's name on the principal's behalf.

Notarization is not stated as a mandatory requirement for validity, but it creates a legally important presumption: a signature on a power of attorney is presumed to be genuine if the principal acknowledges the signature before a notary public or other individual authorized by law to take acknowledgments. In practice, virtually all Montana POAs are notarized because that presumption is essential for agents dealing with banks, title companies, and government agencies.

No separate witness requirement applies to a financial POA under the Uniform Power of Attorney Act. The statutory form power of attorney set out at Mont. Code Ann. 72-31-353 calls for notarization with a notary's signature, date, and seal.

Third-Party Acceptance

Mont. Code Ann. 72-31-324 protects agents presenting acknowledged POAs. A person who accepts an acknowledged POA in good faith, without actual knowledge of problems, may rely on the document as valid and effective. The accepting party may request an agent's sworn certification, an English translation, or a legal opinion, but must generally act within seven business days of presentation. Under Mont. Code Ann. 72-31-325, a person who refuses without lawful excuse to accept a properly acknowledged POA faces court-ordered acceptance and liability for the agent's reasonable attorney fees and costs.

What a Montana Agent Can and Cannot Do

Fiduciary Duties Under Mont. Code Ann. 72-31-319

Mont. Code Ann. 72-31-319 sets out the duties that govern an agent who accepts a Montana POA. The agent must:

• Act in accordance with the principal's reasonable expectations to the extent actually known, and otherwise act in the principal's best interest.
• Act loyally for the principal's benefit and avoid conflicts of interest that impair impartial judgment.
• Act in good faith.
• Exercise the care, competence, and diligence ordinarily exercised by agents in similar circumstances.
• Keep records of all receipts, disbursements, and transactions made on the principal's behalf.
• Cooperate with any person who has authority to make health care decisions for the principal.
• Attempt to preserve the principal's estate plan to the extent known, when consistent with the principal's best interest.

An agent who holds professional expertise is held to the higher standard that expertise entails. An agent who violates these duties may be personally liable for losses caused to the principal or the principal's estate.

Hot Powers Requiring a Specific Grant

Mont. Code Ann. 72-31-336 lists eight categories of authority that an agent cannot exercise unless the POA document explicitly grants each one. These high-stakes powers include:

• Creating, amending, revoking, or terminating an inter vivos trust.
• Making gifts of the principal's property.
• Creating or changing rights of survivorship.
• Creating or changing beneficiary designations.
• Delegating the agent's authority granted under the POA.
• Waiving the principal's right to be a beneficiary of a joint and survivor annuity.
• Exercising fiduciary powers the principal holds over another trust or estate.
• Disclaiming property, including a power of appointment.

A general grant of authority does not satisfy the specific-grant requirement for these powers. Each must be individually authorized in the document. In addition, an agent who is not the principal's ancestor, spouse, or descendant may not use these powers to benefit themselves or persons they support unless the POA explicitly permits it.

Health Care Decisions and Medical POA in Montana

Montana law keeps financial and medical authority in separate legal frameworks. A financial POA under Mont. Code Ann. 72-31-301 et seq. does not authorize the agent to make health care decisions.

Medical and end-of-life decision-making authority is governed by the Montana Rights of the Terminally Ill Act, Mont. Code Ann. sections 50-9-101 through 50-9-111. Under Mont. Code Ann. 50-9-103, any adult of sound mind may execute a written declaration directing their physician or advanced practice registered nurse to withhold or withdraw life-sustaining treatment that only prolongs dying, when the person has a terminal condition and can no longer make or communicate decisions.

Two Declaration Forms

Montana's statute provides two forms for the declaration. The first form is a direct physician directive, in which the declarant personally instructs healthcare providers. The second form names a designee, a qualified adult authorized to make life-sustaining treatment decisions on the declarant's behalf when the declarant is unable to do so, with an alternate designee if the primary is unavailable or unwilling.

The law also recognizes a separately executed power of attorney that contains authorization over life-sustaining treatment decisions as a valid declaration under section 50-9-103, provided it satisfies that section's requirements.

Execution Requirements for a Healthcare Declaration

Under Mont. Code Ann. 50-9-103, the declaration must be signed by the declarant, or by another person at the declarant's direction, and must be witnessed by two individuals. This two-witness requirement distinguishes healthcare declarations from the financial POA, which requires only notarization and no witnesses.

A healthcare provider who receives a declaration must include it in the patient's medical record and promptly inform the patient if the provider is unwilling to comply with its terms.

Revocation of a Healthcare Declaration

Under Mont. Code Ann. 50-9-104, a person may revoke a healthcare declaration at any time and in any manner, without regard to mental or physical condition. Revocation becomes effective once communicated to the attending physician or other healthcare provider. A healthcare provider or emergency responder who witnesses a revocation must act on it immediately and notify the attending physician at the earliest opportunity.

Revoking or Ending a Montana Power of Attorney

Under Mont. Code Ann. 72-31-310, a financial power of attorney terminates when:

• The principal dies.
• The principal revokes the POA.
• The POA provides that it terminates upon a specified event or date, and that event occurs or date arrives.
• The purpose of the POA is accomplished.
• The principal becomes incapacitated, if the POA is not durable.

An agent's authority terminates separately when the agent dies, becomes incapacitated, or resigns. If an action is filed for the dissolution or annulment of the agent's marriage to the principal, or for their legal separation, the agent's authority terminates unless the document expressly provides otherwise. The law also provides a good-faith protection: acts performed by an agent without actual knowledge that authority has terminated remain valid and binding on the principal and successors.

To revoke a POA, a principal should execute a written revocation document while not incapacitated and provide written notice to the agent and to any institutions currently relying on the POA. Notarizing the revocation is advisable. If the original POA was used for real property transactions and placed on record, the revocation should also be recorded.

For an overview of how power of attorney law works across all states, see our national Power of Attorney guide.

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This page provides general legal information about Montana power of attorney laws and is not legal advice. Montana estate planning and incapacity planning involve individual circumstances that a licensed attorney can assess. Consult a qualified Montana attorney before executing or relying on any power of attorney document.

Last reviewed: May 2026. Governing statutes: Mont. Code Ann. 72-31-301 through 72-31-367 (Montana Uniform Power of Attorney Act) and Mont. Code Ann. 50-9-101 through 50-9-111 (Montana Rights of the Terminally Ill Act).