Son found mother's will 23 years after her death: The Supreme Court explained whether inheritance rights can be reviewed

Inheritance disputes often arise after the formalization of inheritance rights has been completed, when one of the heirs tries to revise previously reached agreements. In such cases, the key issue is whether the newly discovered circumstances truly indicate the presence of a legally significant error during the conclusion of the transaction and whether they can affect the stability of civil turnover.

In the Supreme Court ruling dated June 17, 2026, in case No. 554/1247/24, the Cassation Civil Court considered a dispute regarding the invalidation of a certificate of inheritance rights and an agreement on the distribution of inherited property due to the discovery of the testator's will more than two decades after the opening of the inheritance.

Circumstances of the case

The plaintiff applied to the court with demands to invalidate and cancel the certificate of inheritance rights under the law issued to the husband of his mother, to invalidate the agreement on the distribution of inherited property concerning the transfer of an apartment to another heir, and to recognize his ownership rights to the disputed apartment.

After the mother's death, the first-order heirs were her son and husband. In 2001, they received certificates of inheritance rights under the law and on the same day concluded a notarized agreement on the distribution of inherited property. According to this agreement, the testator's husband received an apartment and a car, and the son received a residential house with a land plot.

After the death of the mother's husband in 2023, the plaintiff, while cleaning the apartment, discovered two wills of his mother, one of which provided for the transfer of all property to him.

In his opinion, had he known about the existence of these wills in 2001, he would not have concluded the agreement on the distribution of inherited property. Therefore, he believed that the transaction was concluded under the influence of an error.

The courts of first and appellate instances denied the claim, after which the plaintiff filed a cassation appeal to the Supreme Court.

Position of the Supreme Court

The Supreme Court indicated that according to part one of Article 229 of the Civil Code of Ukraine, if a person who concluded a transaction was mistaken about circumstances of essential importance, such a transaction may be recognized as invalid by the court.

An error is of essential importance if it concerns the nature of the transaction, the rights and obligations of the parties, or such properties and qualities of the property that significantly reduce its value or the possibility of using it for its intended purpose. An error regarding the motives of the transaction is not of essential importance, except in cases established by law.

At the same time, an error is understood as an incorrect, mistaken, or untrue perception by a person about the nature or elements of the transaction they are concluding. A person must prove that such an error actually existed and that it was of essential importance to support their claim for invalidation of the transaction.

The court emphasized that the circumstances about which the party was mistaken must exist at the moment the transaction was concluded.

An error resulting from one's own negligence, ignorance of the law, or its incorrect interpretation by one of the parties is not grounds for recognizing a transaction as invalid.

The Supreme Court noted that the plaintiff did not dispute the fact of the voluntary conclusion of the agreement on the distribution of inherited property, and the agreement itself was voluntarily executed by the parties for more than twenty years.

The Court also pointed out that the plaintiff's claim of ignorance regarding the existence of a notarized will, which he learned about only 23 years after the testator's death and which was kept in the inherited apartment, cannot be considered an error under the influence of which he agreed to receive the certificate of inheritance rights under the law and then concluded an agreement on the voluntary division of inherited property with another heir based on that certificate.

The Supreme Court decided that the plaintiff did not prove the objective existence of an error under the influence of which he received the certificates of inheritance rights under the law and concluded the agreement on the distribution of inherited property, therefore the stated claims are unfounded.

Regarding the demand to invalidate the certificate of inheritance rights, the Supreme Court separately noted that the certificate of inheritance rights is not a transaction by its nature.

The provisions of the Civil Code of Ukraine and other laws on transactions, in particular the norms of Chapter 16 of the Civil Code of Ukraine, cannot be applied to the invalidity of the certificate of inheritance rights.

The court also noted that the testator's husband lawfully acquired the right to inheritance under the law after his wife's death and had the right to the corresponding share of the inherited property.

Thus, the Supreme Court left the cassation appeal without satisfaction and the decisions of the previous instances unchanged.

The court confirmed that the discovery of a will many years after the inheritance has been formalized does not prove the existence of a significant error within the meaning of Article 229 of the Civil Code of Ukraine. The Supreme Court also emphasized that the certificate of inheritance rights is not a transaction, so the grounds for invalidity of transactions cannot automatically apply to disputes regarding such a certificate.

This legal position highlights the importance of the principle of stability of civil legal relations and the necessity to prove a legally significant error that existed at the time the transaction was concluded.

Additionally, read about another position of the Supreme Court where a will was canceled shortly before death and without the family's knowledge: what the Court said about heirs' rights.

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