Is a Will by Dementia Patient Valid in South Korea? Testamentary Capacity Analysis | Atlas Legal
Table of Contents
- 1. Can a Dementia Patient Make a Will in South Korea?
- 2. What is Testamentary Capacity?
- 3. What Standards Does the Korean Supreme Court Use to Determine Testamentary Capacity?
- 4. Supreme Court Precedents Recognizing Valid Wills
- 5. Supreme Court Precedents Ruling Wills Invalid
- 6. Validity of Wills Made Before Adult Guardianship Commencement
- 7. Will Drafting Guide to Prevent Inheritance Disputes
- 8. FAQ
Client Inquiry: “My mother drafted a will while diagnosed with dementia. Is this will valid?” This was a question brought to Atlas Legal by a family of a mid-sized company owner in Songdo, Incheon, South Korea. The mother had an adult guardianship commencement petition in progress, with a temporary guardian already appointed. A dispute arose among the heirs regarding the validity of the will. (This case has been adapted from an actual case for clarity of understanding.)
Why Did Wills by Dementia Patients Become an Important Legal Issue in South Korea?
South Korea entered a super-aged society in 2025, with the elderly population accounting for more than 20% of the total population. According to the Korea Central Dementia Center, as of 2023, 1 in 10 people aged 65 and over suffers from dementia, expected to reach 3.02 million by 2050. Wills by dementia patients become an important legal issue between respecting the individual’s right to self-determination and protecting heirs’ rights. The problem is that dementia progresses gradually over a long period and fluctuates between improvement and deterioration. Therefore, testamentary capacity cannot be denied solely based on the fact of “dementia diagnosis,” and the specific condition at the time of making the will must be determined individually. The Korean Supreme Court has specified these judgment standards in more than 15 decisions. Atlas Legal will systematically analyze Supreme Court precedents to explain in detail the standards for determining testamentary capacity and methods to prevent inheritance disputes.
1. Can a Dementia Patient Make a Will in South Korea?
Dementia Diagnosis and Testamentary Capacity Are Separate
A dementia diagnosis does not immediately mean lack of testamentary capacity. The court ruled that “even if the deceased’s condition at that time could be medically diagnosed as dementia or mental incompetence with insufficient decision-making capacity, such circumstances alone cannot conclusively determine that the deceased lacked mental capacity at the time of drafting the notarized will” (Daegu District Court Decision 2022. 7. 21., 2019Gahap205484).
This is because dementia symptoms characteristically fluctuate between improvement and deterioration. Therefore, not all legal acts during the dementia diagnosis period are invalid; rather, the condition at the time of each legal act must be determined individually.
Age of Testamentary Capacity and Testamentary Capacity in Korean Law
Korean Civil Act Article 1061 stipulates “a person who has not reached 17 years of age may not make a will,” establishing the testamentary age. Those 17 years or older can make wills without legal representative consent even if they are minors. Additionally, adults under guardianship and adults under limited guardianship also have testamentary capacity if they are 17 years or older (Civil Act Article 1062).
However, adults under guardianship can make wills only when mental capacity is restored, and at that time, a doctor must note the state of mental recovery in the will document and sign and seal it (Civil Act Article 1063, Paragraphs 1 and 2).
2. What is Testamentary Capacity?
Definition of Testamentary Capacity
Although the Korean Civil Act does not clearly define testamentary capacity in any provision, legal theory generally defines testamentary capacity as “the capacity to validly make a will.” Since a will is also a legal act, there is no dispute that the testator needs testamentary capacity.
Precedents state that “testamentary capacity is the mental discernment ability to understand the intent of the will, and considering its nature, it does not mean the degree required for property acts” (Seoul High Court Decision 2011. 10. 4., 2010Na101334), applying more relaxed standards than general property acts.
Relationship Between Mental Capacity and Testamentary Capacity
Mental capacity means “mental ability or intelligence to rationally judge the meaning or consequences of one’s actions based on normal recognition and predictability” (Supreme Court Decision 2002. 10. 11., 2001Da10113). Legal acts by persons without mental capacity are invalid.
Legal theory and precedents generally evaluate testamentary capacity similarly to mental capacity. In actual judgments, there are cases ruling that “testamentary capacity is a matter of mental capacity” (Seoul High Court Decision 2023. 4. 20., 2021Na2044594). Therefore, without testamentary capacity, there is no mental capacity, and without mental capacity, the will is also invalid.
3. What Standards Does the Korean Court Use to Determine Testamentary Capacity?
Comprehensive Consideration Factors
The court stated “the presence or absence of testamentary capacity is a matter of fact finding, and should be determined individually according to specific cases by comprehensively considering whether the testator had the capacity to understand and judge the contents of the will and its legal effects, that is, the testator’s judgment ability at the time of making the will, disease status, will contents, circumstances at the time of drafting the will, previous intentions, and relationship with the beneficiary” (Seoul Central District Court Decision 2010. 12. 23., 2010Gahap20414).
15 Specific Judgment Standards
Synthesizing Korean Supreme Court and lower court precedents, the following factors are considered when determining testamentary capacity.
| Category | Judgment Criteria | Details |
|---|---|---|
| Formal Requirements | 1. Satisfaction of Oral Declaration Requirement | Whether testator orally conveyed will’s intent; simply nodding is insufficient |
| 2. Direct Signature and Seal | Whether able to sign without others’ help; invalid if wrist was held | |
| Physical Factors | 3. Health Condition at Time of Will | Age, disease progression, presence of delirium, etc. |
| 4. Type and Pattern of Disease | MMSE test results, physical examination report, Alzheimer’s diagnosis, etc. | |
| 5. Communication Capability | Whether could express intent understandably despite mobility difficulties | |
| 6. Consciousness Clarity | Whether consciousness was clear at time of will or in semi-comatose state | |
| Content Factors | 7. Consistency with Usual Intentions | Whether will content is unusual, excludes only specific persons |
| 8. Complexity of Will Content | Whether simple content or complex content with multiple properties and beneficiaries | |
| 9. Circumstances Leading to Will | Preparation process before will, circumstances of draft preparation, etc. | |
| 10. Legal Meaning and Effect | Whether could understand the legal effects of the will | |
| Procedural Factors | 11. Interval Between Illness Deterioration and Will | Period between will and death, timing of illness deterioration |
| 12. Composition of Procedure Participants | Conflicts of interest among notary, witnesses, and beneficiaries | |
| 13. Whether Objections Raised | Whether any participant raised issues | |
| 14. Consistency with Draft | Whether structure and content match previously prepared draft | |
| 15. Reasonableness | Whether content can be considered unreasonable from testator’s perspective |
4. Precedents Where Wills Were Recognized as Valid
Facts: After being diagnosed with lung cancer, the deceased sensed impending death as the condition worsened and prepared a draft will in advance, delivering it to the notary attorney. On the day of the will, the deceased orally declared the will’s intent again in the hospital room, and the notary attorney read the draft content to confirm consistency. Death occurred 6 days after making the will.
Judgment: The Supreme Court recognized the will as valid, finding that the deceased had clear consciousness and personally reviewed all related documents before signing and sealing.
Facts: The deceased was hospitalized 4 months after being discharged following stage 3 lung cancer surgery, and made a will 2 weeks after hospitalization. At that time, suffering from extreme pain, slow responses, and difficulty eating. Answered the notary’s questions with “do it that way,” and died 2 months after making the will.
Judgment: The Supreme Court recognized the validity of the will, determining that the deceased had mental discernment ability, noting direct signing with accurate handwriting, simple content with one parcel of real estate and only 2 beneficiaries.
Facts: The deceased had delirium after brain tumor surgery, and scored 23 points on the MMSE test (out of 30, with 24 or higher being normal) on the day of making the will. The content was bequeathing over 500,000 shares to a foundation. The deceased had previously written an award acceptance speech, delivered remarks at an awards ceremony, and gave interviews to reporters.
Judgment: The Supreme Court recognized testamentary capacity, finding that the will content had the same basic structure as the pre-surgery draft, the scale of bequeathed property was large but not complex, and the content was reasonable from the deceased’s perspective.
Facts: The deceased was lying on a sofa receiving IV fluids with support due to terminal stomach cancer, and died the day after making the will. Although in a small voice, answered understandably “naturally it should go to the eldest son,” and signed and sealed directly with clear handwriting.
Judgment: The court recognized the validity of the will, considering that the deceased could express intent despite mobility difficulties and signed directly. Even if death occurred the day after making the will, it is valid if the deceased could express intent at the time of making the will.
5. Precedents Where Wills Were Ruled Invalid
Facts: The deceased could not speak due to a tube inserted in the throat after bronchial resection surgery, and expressed intent through facial expressions, gestures, and lip movements. At the time of making the will, was already in a medically semi-comatose state, and only nodded when staff read the draft content. The prospective beneficiary held the wrist to enable signing.
Judgment: The Supreme Court ruled it invalid, finding lack of mental capacity and that the intent of the will was not orally declared.
Facts: The deceased made an oral will in a life-threatening condition due to chronic myeloid leukemia and stomach cancer. Did not recognize the eldest daughter-in-law or called electrical wires on the ceiling snakes, and could only nod or say “mm,” “uh.” The will content completely excluded the son from the divorced former wife.
Judgment: The Supreme Court remanded the case, ruling that merely nodding or saying “mm,” “uh” cannot be considered oral declaration of the will’s intent.
Facts: The deceased was diagnosed with Alzheimer’s-type dementia about 1 year and 4 months before drafting the will. The will content excluded only the third son who had been favored for decades from inheritance, with no special circumstances showing a complete attitude change in 4 months.
Judgment: The court ruled it invalid, noting that “the mental capacity required for will drafting is demanded at a higher level than mental capacity for litigation delegation or deposit withdrawal,” finding lack of mental capacity to understand the legal meaning and effects.
Facts: The deceased had difficulty recognizing the situation due to disorientation and memory impairment, and could only nod or shake head to the notary’s questions due to dysarthria. The handwriting of the signature was unrecognizable, and the notary and participants stamped the seal instead. Death occurred 2 days after making the will.
Judgment: The court ruled it invalid, considering that the content of giving most of the deceased’s property only to the second son, bypassing the eldest son, was very unusual, and only the prospective beneficiary, not the child who provided care, attended.
6. Validity of Wills Made Before Adult Guardianship Commencement
Significance of Supreme Court Decision 2022Da261237
The subject decision, Supreme Court Decision December 1, 2022, 2022Da261237, addressed a case where the validity of a dementia patient’s will was questioned when made after an adult guardianship commencement petition was filed and a temporary guardian was appointed.
In this case, the deceased received a preliminary disposition appointing a temporary guardian on December 30, 2016, drafted a will on March 24, 2017, had the adult guardianship commencement judgment finalized on February 20, 2018, and died on July 20, 2020.
Supreme Court’s Judgment
The Supreme Court ruled as follows:
First, even when a temporary guardian is appointed through preliminary disposition under Article 62(1) of the Family Litigation Act, the person under guardianship can make a will without the temporary guardian’s consent as long as mental capacity exists. This is because Civil Act Article 1062 provides that Civil Act Articles 10 and 13, which are provisions related to legal capacity, do not apply to wills by adults under guardianship and adults under limited guardianship.
Second, Civil Act Article 1063(2) (requirement for doctor’s notation of mental recovery state) applies only when adult guardianship has commenced, and does not apply when only a temporary guardian has been appointed before adult guardianship commencement.
7. Will Drafting Guide to Prevent Inheritance Disputes in South Korea
Securing Evidence to Prove Testamentary Capacity
For elderly or ill persons, it is important to secure evidence that can prove mental capacity at the time of making the will. Please consider the following:
1. Secure Medical Records
Secure medical records and MMSE test results from times close to before and after making the will. While 24 points or higher is evaluated as normal, there are cases where testamentary capacity was recognized even with 20 points or higher (Supreme Court Decision 2011Da87259).
2. Video Recording
Video recording the will-making process can objectively prove the condition at the time of making the will. In the subject decision, video footage taken during will drafting was important evidence.
3. Consistency with Usual Intentions
Ensure will content is consistent with usual intentions. Suddenly excluding only specific heirs or unusual content causes disputes.
4. Professional Presence
For notarized wills, the notary and witnesses should have no conflicts of interest with prospective beneficiaries. If possible, please consult with an attorney.
Choosing Will Format
Korean Civil Act recognizes 5 will formats: holographic will, audio recording, notarized will, secret will, and oral will. For dispute prevention, notarized wills are recommended. With notary participation, it is easy to meet formal requirements and prove circumstances at the time of making the will.
Atlas Legal provides legal services throughout the entire inheritance process, including will drafting consultation, evidence preparation for securing testamentary capacity, representation in actions for confirmation of invalidity of will, and representation in statutory reserved portion claim lawsuits.
8. FAQ
Atlas Legal is located in Songdo, Incheon, South Korea, providing legal services in corporate law, corporate disputes, corporate advisory, and corporate crimes (fraud, embezzlement, breach of trust, tax law, customs law). We protect our clients’ rights by accurately applying Korean Supreme Court precedents in inheritance disputes related to testamentary capacity determination. We provide professional legal services throughout the entire inheritance process, from will drafting consultation to actions for confirmation of invalidity of will and statutory reserved portion claim lawsuits.
※ This article was written with reference to Shin Eun-young, “Wills of Persons with Reduced Intellectual Capacity – With Commentary on Supreme Court Decision December 1, 2022, 2022Da261237,” Seoul Law Review Vol. 33 No. 1, 2025.