Here's a comprehensive legal discussion on the Validity of Unnotarized Deeds of Donation After the Donor’s Death under Philippine law:

1. Overview of a Deed of Donation in Philippine Law

A deed of donation is a legal instrument by which a donor gratuitously transfers ownership of a property to a donee, who accepts it. The governing laws include:

Articles 725 to 746 of the Civil Code
Applicable provisions of Book II (Property) and Book IV (Obligations and Contracts)

Donations may be:

Inter vivos (between living persons)
Mortis causa (effective upon death, like a will)

2. Requirements for Validity of a Donation

A. General Requirements

Donor must have capacity to donate (Art. 735)
Donee must accept the donation (Art. 746)
Form requirements depend on:
- The type of property (movable or immovable)
- The value of the donation

B. Formalities for Immovable Property

For immovable properties (e.g., land, houses):

The donation must be in a public instrument (i.e., notarized).
It must contain:
- A description of the property donated
- The value of charges the donee assumes (if any)
Acceptance must also be in a public instrument (can be in same or separate instrument) and:
- Must be notified to the donor if in a separate document (Art. 749)

⚠️ Notarization is essential for validity—not merely for registration.

3. Effects of Lack of Notarization

A. If the Deed of Donation Is Not Notarized

The donation is void if it involves immovable property and is not in a public instrument.
An unnotarized deed of donation of real property has no legal effect.
The acceptance, even if made, has no legal force unless also notarized.

📌 Example: A private, unnotarized deed of donation of a house—even if signed by both parties—cannot transfer ownership or be registered with the Registry of Deeds.

4. What Happens After the Donor's Death

Once the donor dies, any attempt to validate or enforce the unnotarized deed faces critical legal obstacles:

A. For Donations Inter Vivos

These are intended to take effect during the donor’s lifetime.
Donation must be perfected and valid before the donor’s death.
If unnotarized, the donation of real property is void ab initio.
Heirs may rightfully object and recover the property.

B. For Donations Mortis Causa

These are not donations under the Civil Code but are governed by succession law.
Such donations must comply with the formalities of a will:
- Must be in a public or holographic will
- Must observe probate requirements
A simple deed labeled “donation mortis causa” but not executed as a valid will is void.

5. Is Notarization Curable After Death?

No. The following principles apply:

Notarization is not a mere procedural formality; it is substantive for validity in donations of immovable property.
Ratification post-mortem is not allowed for defective deeds where the defect concerns an essential element (i.e., form).
The death of the donor cuts off any opportunity to validly execute or correct the form of donation.

6. Exceptions or Related Scenarios

A. Donation of Movable Property

If under ₱5,000: No written form required.
If ₱5,000 or more: Must be in writing, but not necessarily notarized.

B. Doctrine of Estoppel

In rare cases, courts have upheld equitable estoppel against heirs who benefited from the donation or were aware of it and failed to object.
However, estoppel cannot cure a void donation of immovable property lacking a public instrument.

7. Registration Is Not a Cure

The Registry of Deeds requires notarized documents to register property transfers.
Even if a private deed were mistakenly registered, registration cannot legalize a void donation.

8. Relevant Jurisprudence

Heirs of Inting v. CA (G.R. No. 111370) – Reinforced the requirement of notarization for validity.
Vales v. Villa (G.R. No. L-47115) – Distinguished donation mortis causa from inter vivos, applying succession law to the former.
Cruz v. CA – Reiterated that acceptance in proper form is indispensable.

9. Summary of Legal Consequences

Scenario	Unnotarized Donation Status	After Donor’s Death
Real property	Void ab initio	Cannot be ratified or cured
Personal property (≥ ₱5,000)	Void if not in writing	Cannot be cured
Mortis causa (not in will form)	Void	Cannot substitute for a will
Registration	Not allowed without notarization	No legal effect if deed is void

10. Final Legal Takeaway

In the Philippines, an unnotarized deed of donation involving real property is void, and such invalidity cannot be remedied after the donor’s death. For a donation to be effective, compliance with the formal requirements, particularly notarization, is mandatory. Otherwise, heirs can rightfully recover the property, and the donee cannot rely on the defective deed to claim ownership.

If needed, parties should consult a notary public and legal counsel to ensure all formalities are met during the donor’s lifetime.

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