Health Care Power of Attorney Requirements in Montana

At a glance

Montana's general durable health care power of attorney is unusually lightly codified. The governing part contains only Mont. Code Ann. §§ 72-5-501 and 72-5-502. It requires a written agent designation with words showing that authority survives incapacity or begins upon incapacity, but it does not publish a form or add a witness or notary formality.

This is distinct from the Rights of the Terminally Ill Act in Title 50, chapter 9, which governs a narrower declaration about life-sustaining treatment. It is also distinct from Montana's financial Uniform Power of Attorney Act, which expressly excludes powers to make health care decisions (§ 72-31-303(2)).

Requirements one by one

Governing law and document

Section 72-5-501 defines a durable health care power as a writing in which the principal designates an attorney-in-fact or agent and uses durability or springing language. Part 5 provides no statutory form. Montana hospitals must recognize the intent of a legally valid health care power concerning treatment (§ 50-5-110(1)(g)).

Who can sign

The statute describes the principal as making the written designation (§ 72-5-501(1)). This two-section part does not state a special minimum age, define the principal's capacity threshold, separately prescribe a signature, or authorize a directed signer. Those matters should not be filled in from the financial POA act, because that act excludes health-care-decision powers (§ 72-31-303(2)).

Witnesses or notary

Neither § 72-5-501 nor § 72-5-502 requires a witness or notarization for the general health care power. The express statutory requirement is the written designation plus words showing the intended effect of later disability or incapacity.

The witness rules for a Title 50 terminal-illness declaration answer a different question. Likewise, the financial UPOAA's execution and acknowledgment rules do not govern a power to make health care decisions (§ 72-31-303(2)).

Who cannot witness or serve

Because the general statute does not require witnesses, it has no witness- qualification list. Sections 72-5-501 and -502 also state no occupation, relationship, facility, or provider bar on the selected agent.

If a guardian is later appointed, the agent becomes accountable to the guardian. The guardian has the same power the principal would have had to revoke or amend the health care power (§ 72-5-501(2)).

When the agent can act

The wording chosen controls. A writing may say the power is not affected by later disability or incapacity, making existing authority durable. Or it may say the power becomes effective upon disability or incapacity, making it springing. Similar words showing the same intent work (§ 72-5-501(1)). Part 5 does not identify a clinician or other person who must determine incapacity.

Powers and limits

Part 5 does not supply a default list of medical powers or categorical treatment limits; the written grant defines the authority. Section 50-5-110(1)(g) recognizes a health care power "concerning treatment," and the current proxy hierarchy places an agent appointed in a medical durable power of attorney ahead of family and default proxies (§ 50-5-1311).

Montana separately regulates terminal-care declarations and mental-health advance directives. Their specialized powers and formalities should not be mistaken for defaults governing every general health care power.

How to revoke

Section 72-5-502 refers to express revocation but does not prescribe a signed, oral, destruction, or delivery method. As to an agent or another person who acts in good faith, revocation or termination is not effective until that person has actual knowledge (§ 72-5-502(1)-(2)). A later guardian may revoke or amend under § 72-5-501(2).

No automatic divorce or separation rule for a spouse-agent appears in this health-care-POA part. The financial UPOAA's spouse-agent rule cannot be imported because health care powers are excluded from that act (§ 72-31-303(2)).

Out-of-state directives

The general health-care-POA part has no express reciprocity section. Montana does recognize an out-of-state terminal-illness declaration that is substantially similar to § 50-9-103 and valid where executed, but that rule is effective only "for purposes of" the Rights of the Terminally Ill Act (§ 50-9-111). It is not a general portability rule for every health care power.

What trips people up

• The financial POA formalities do not carry over. Section 72-31-303(2) expressly excludes a power to make health care decisions.
• The durability words matter. The writing must show that authority survives incapacity or becomes effective upon incapacity (§ 72-5-501(1)).
• A terminal-illness declaration is not the same instrument. Title 50, chapter 9 has its own rules and only addresses the declaration within that act.

Common questions

Do I need two witnesses or a notary? Not under the general health-care-POA provisions in §§ 72-5-501 and -502. The financial UPOAA is expressly inapplicable (§ 72-31-303(2)).

Does the agent act immediately? It depends on the writing. Montana expressly recognizes both continuing and springing durability language (§ 72-5-501(1)).

Does Montana provide a statutory health care POA form? No form appears in the governing two-section Part 5. The financial statutory form does not authorize health-care decisions.

Will an out-of-state health care POA work? The general Part 5 does not answer that question expressly. Section 50-9-111's reciprocity rule is limited to the separate terminal-illness declaration.

Statutes and sources

• Mont. Code Ann. § 72-5-501 — written designation, durability language, and later guardian. https://leg.mt.gov/bills/mca/title_0720/chapter_0050/part_0050/section_0010/0720-0050-0050-0010.html (accessed 2026-08-08)
• Mont. Code Ann. § 72-5-502 — actual-knowledge protection and termination terms. https://leg.mt.gov/bills/mca/title_0720/chapter_0050/part_0050/section_0020/0720-0050-0050-0020.html (accessed 2026-08-08)
• Mont. Code Ann. § 72-31-303 — financial UPOAA excludes health-care powers. https://leg.mt.gov/bills/mca/title_0720/chapter_0310/part_0030/section_0030/0720-0310-0030-0030.html (accessed 2026-08-08)
• Mont. Code Ann. §§ 50-5-110 and 50-5-1311 — hospital recognition and decisionmaker priority. https://leg.mt.gov/bills/mca/title_0500/chapter_0050/part_0010/section_0100/0500-0050-0010-0100.html and https://leg.mt.gov/bills/mca/title_0500/chapter_0050/part_0130/section_0110/0500-0050-0130-0110.html (accessed 2026-08-08)
• Mont. Code Ann. § 50-9-103(1), (4) — separate terminal-illness declaration formalities and its cross-reference to a health care power of attorney. https://leg.mt.gov/bills/mca/title_0500/chapter_0090/part_0010/section_0030/0500-0090-0010-0030.html (accessed 2026-08-08)
• Mont. Code Ann. § 50-9-111 — limited reciprocity for terminal-illness declarations. https://leg.mt.gov/bills/mca/title_0500/chapter_0090/part_0010/section_0110/0500-0090-0010-0110.html (accessed 2026-08-08)