Codicil Mexico (Codicilo — Modificación al Testamento)

A Codicil Mexico (Codicilo) is a formal testamentary instrument authorized by the Código Civil Federal (CCF) that modifies, adds to, or partially revokes specific clauses or provisions of an existing will (testamento) without replacing the entire original document. The codicil is executed before a Notario Público in compliance with the same formalities required for the type of will it amends — preserving the unchanged provisions of the original testament while incorporating the modifications as an completo part of the testator's (testador's) final testamentary expression.

The legal basis for the codicil in Mexican law is established in Article 1485 of the Código Civil Federal, published in the DOF on 26 May 1928. Article 1485 CCF defines the codicilo as the testamentary act by which the testator modifies the dispositions made in a prior testament, and establishes that it must comply with all the formalities required for a testament (testamento). The codicil does not create a new or separate succession — it supplements and modifies the existing will, and both documents are read together as the complete expression of the testator's wishes regarding the distribution of their patrimony (patrimonio).

Mexican succession law under the CCF distinguishes between several types of testaments that may be modified by codicil: the testamento público abierto (public open will) executed before a Notario Público under Articles 1511 through 1527 CCF, which is the most common form; the testamento público cerrado (public closed will) under Articles 1528 through 1539 CCF; the testamento ológrafo (holographic will) under Articles 1550 through 1554 CCF, which is entirely handwritten and signed by the testator without notarial presence; and the testamento público simplificado (simplified public will) introduced by 2019 reforms for transfers of a single immovable property to a single beneficiary. Each type has specific formal requirements, and the codicil modifying that type of will must satisfy the same formal requirements.

For the testamento público abierto — the predominant form used in Mexican notarial practice — the codicil must be executed before a Notario Público (notary public) with full powers in the testator's state of residence, in the presence of the testator and any legally required witnesses, with the Notario reading the codicil aloud to the testator, the testator confirming its content, and all parties signing before the Notario, who then authorizes the instrument as an escritura pública (public deed) under the Ley del Notariado of the applicable state.

The Dirección del Archivo General de Notarías in each state (for example, the Archivo General de Notarías del Distrito Federal, now CDMX) and the Registro Nacional de Avisos de Testamento (RENAT) operated by the Consejo de la Judicatura Federal through the Colegio de Notarios del Distrito Federal record testaments and codicils. The RENAT is a national electronic registry that allows courts, heirs, and interested parties to verify whether a deceased person left a testament or codicil, accessible through participating notaries across Mexico. Codicils must be reported to the RENAT in the same manner as original testaments under the rules of the Ley del Notariado.

Upon the testator's death, the codicil is presented together with the original testament in the sucesión testamentaria (testate succession proceeding) before a Notario Público (for uncontested successions with competent heirs) or a civil judge (for contested proceedings or where legal obstacles exist). The Notario or judge integrates the original will and all codicils to reconstruct the complete, final testamentary expression of the deceased, applying any modifications made by the codicil to the relevant provisions of the original will.

A Codicil Mexico (Codicilo) is needed whenever a testator wishes to make specific, limited changes to an existing will without the complexity and cost of revoking and rewriting the entire testamentary document. The codicil is the appropriate instrument when the modifications are targeted and the majority of the original will's provisions remain valid and appropriate.

The codicil is needed when a testator wishes to add a new beneficiary (legatario or heredero) to their will following a birth, adoption, marriage, or the formation of a new significant personal relationship — without replacing the provisions relating to previously designated heirs. Under CCF Articles 1281 through 1294 on succession and Articles 1382 through 1399 on legacies (legados), adding a beneficiary through a codicil is the least disruptive modification to an existing testamentary structure.

The document is needed when a testator wishes to remove a beneficiary from their will — for example, following a divorce (divorcio), estrangement, or the death of a previously designated heir. Under CCF Article 1311, heirs who predecease the testator without issue do not automatically transmit the inheritance right, and the codicil can address this contingency explicitly. Following a divorce, Article 1310 CCF provides that provisions in favor of a former spouse are not automatically revoked — a codicil is needed to update the testamentary disposition.

A codicil is needed when a testator wishes to change the executor (albacea) or add a substitute executor, without otherwise modifying the substantive dispositions of the will. The albacea under CCF Articles 1679 through 1788 carries significant responsibility for administering the estate during the succession proceeding, and changes in the testator's confidence in the designated albacea may necessitate a codicil updating that appointment.

The instrument is needed when specific assets mentioned in the will have been sold, transferred, or transformed, and the testator wishes to substitute new assets or adjust the specific legacies (legados específicos) to reflect their current patrimony. Under CCF Article 1484, a legacy of a specifically identified asset that the testator no longer owns at the time of death is generally considered void — a codicil can address this by converting specific legacies to proportional shares or substituting assets.

For testators holding cross-border assets in the United States, Canada, or other countries, a codicil may be needed to add a Mexican international private law clause (DIPr — Derecho Internacional Privado) designating the law applicable to different portions of the estate, or to coordinate the Mexican testamentary dispositions with foreign-law estate planning instruments under CCF Articles 12 through 15 on conflict of laws.

A valid Codicil Mexico under the Código Civil Federal and the applicable state Ley del Notariado must contain the following essential elements to be legally effective as a modification to an existing testament.

Testator Identification: Full legal name, RFC (Registro Federal de Contribuyentes), CURP (Clave Única de Registro de Población), date and place of birth, marital status (estado civil), current domicile, and official identification document number (INE/IFE, passport) of the testator (testador). The testator must have plena capacidad jurídica (full legal capacity) — meaning they must be at least 16 years of age for testamentary capacity under Article 1306 CCF and must be in full possession of their mental faculties at the time of executing the codicil.

Reference to the Original Testament: Precise identification of the original will being modified — the date of execution, the Notario Público before whom it was executed, the protocol number (número de protocolo) of the notarial deed, the state and city, and the Registro Nacional de Avisos de Testamento (RENAT) registration number if available. This reference establishes the legal continuity between the original will and the codicil.

Declaration of Intent: An unambiguous declaration by the testator that the codicil is made freely, voluntarily, and with full knowledge of its legal effects — confirming testamentary capacity (capacidad testamentaria) and absence of undue influence, fraud, or error under CCF Articles 1297 through 1299.

Specific Modifications: A precise and clear statement of each modification to the original will — identifying the specific clause (cláusula), article, or provision being amended, adding, or revoked; the text of the original provision; and the text of the replacement or addition. Where a beneficiary is being added, their full legal name, RFC, CURP, and relationship to the testator must be stated. Where property is being bequeathed, it must be precisely identified by property description, registration data in the Registro Público de la Propiedad, and any cadastral (catastro) references.

Confirmation of Unchanged Provisions: An explicit statement that all provisions of the original testament not expressly modified by the codicil remain in full force and effect (en plena vigencia y eficacia) as originally executed.

Notarial Formalities: For a testamento público abierto (the most common type), the codicil must be authorized by a Notario Público with jurisdiction in the testator's state, read aloud to the testator in the presence of any legally required witnesses, signed by all parties, and incorporated as an escritura pública numbered in the Notario's protocol. The Notario must send an aviso de testamento to the RENAT within five business days of authorization under the applicable state Ley del Notariado.

Revocation of Prior Codicils: Where the testator has previously executed codicils, the new codicil should expressly state whether it supersedes, supplements, or partially revokes any prior codicil. Under CCF Article 1494, a later testamentary instrument revokes a prior one to the extent of inconsistency — but expressly addressing the relationship between codicils prevents ambiguity in the sucesión proceeding before the Notario Público or civil judge.

Estate and Succession Coordination: Where the codicil modifies legacy provisions in a will that is part of a broader estate plan — including fideicomisos sucesorios (testamentary trusts) under the Ley General de Títulos y Operaciones de Crédito, life insurance beneficiary designations, AFORE beneficiary designations under the Ley del Sistema de Ahorro para el Retiro, and INFONAVIT housing fund survivor rights — the codicil should be drafted in coordination with those instruments to avoid contradictions. Assets held in a fideicomiso sucesorio are not disposed of by the will or codicil but by the trust deed (contrato de fideicomiso) — a distinction critical to avoiding double dispositions or gaps in the testator's overall succession plan.

Forms-legal.com provides this Codicil Mexico template as a preparatory resource for individuals planning testamentary modifications under the Código Civil Federal. Under Mexican law, a codicil modifying a testamento público abierto must be executed before a Notario Público — it cannot be executed as a private document. Consulting with a Notario Público or a licensed abogado specializing in sucesiones and derecho hereditario before making testamentary modifications is essential to ensure that the codicil integrates properly with the original will and achieves the testator's intended estate plan.