In the Philippines, marriage is legally defined as an inviolable social institution and the foundation of the family. Because the state is mandated to protect marriage, the process of dissolving a union is rigorous. Unlike most countries, the Philippines does not have a general divorce law. Instead, individuals seeking to end a marriage must navigate either a Declaration of Nullity or an Annulment.

1. Nullity vs. Annulment: Key Distinctions

While often used interchangeably in casual conversation, these terms represent distinct legal concepts under the Family Code of the Philippines.

Feature	Declaration of Nullity	Annulment
Status of Marriage	The marriage is Void ab initio (void from the beginning). It never legally existed.	The marriage is Voidable. It is valid until legally set aside by a court.
Grounds	Serious defects present at the time of celebration (e.g., incest, bigamy).	Defects in consent or physical capacity existing at the time of marriage.
Prescription	The action does not expire; it can be filed at any time.	Generally must be filed within five years of discovery or reaching a certain age.
Legal Basis	Articles 35, 36, 37, and 38 of the Family Code.	Article 45 of the Family Code.

2. Declaration of Absolute Nullity (Void Marriages)

A petition for the Declaration of Absolute Nullity applies to marriages that are dead on arrival. Under the law, these unions are considered to have no legal effect whatsoever.

Common Grounds (Article 35)

Lack of Authority: Marriages solemnized by any person not legally authorized to perform marriages.
No License: Marriages solemnized without a valid marriage license (except in specific exempt cases like marriages in articulo mortis).
Bigamous/Polygamous: Marriages contracted by any person during the subsistence of a previous valid marriage.
Mistake in Identity: Marriages where one party was mistaken as to the identity of the other.

Psychological Incapacity (Article 36)

This is the most frequently cited ground in the Philippines. It refers to a party’s inability to comply with the essential marital obligations (procreation, mutual love, respect, and support).

Evolution of the Law: Following the landmark case of Tan-Andal v. Andal, the Supreme Court clarified that psychological incapacity is a legal, not a medical, concept. It does not require a clinical diagnosis by a psychologist or psychiatrist, though expert testimony remains highly persuasive.
Requirements: The incapacity must be characterized by gravity, juridical antecedence (existing at the time of the wedding), and incurability (in the legal sense of being unable to fulfill marital duties).

Incestuous and Void by Reason of Public Policy (Articles 37 & 38)

Between ascendants and descendants.
Between brothers and sisters (full or half-blood).
Between collateral blood relatives up to the fourth civil degree (first cousins).
Between step-parents and step-children.
Between a party and the surviving spouse of the other’s parent/child.

3. Annulment (Voidable Marriages)

Under Article 45, a marriage may be annulled for causes existing at the time of the marriage. These marriages are valid until the moment the court issues a decree of annulment.

Lack of Parental Consent: If a party was between 18 and 21 years old and the marriage was celebrated without parental consent (unless the party continued to cohabit freely after reaching 21).
Insanity: If either party was of unsound mind at the time of the marriage.
Fraud: Limited to specific instances, such as non-disclosure of a prior conviction involving moral turpitude, concealment of pregnancy by another man, or concealment of a sexually transmitted disease (STD).
Force, Intimidation, or Undue Influence: If consent was obtained through external pressure.
Impotence: Physical inability to consummate the marriage, where the condition is permanent and appears incurable.
Serious STD: If either party has a sexually transmitted disease that is serious and appears to be incurable.

4. The Legal Process

The process is strictly judicial and typically involves several stages:

Filing of Petition: The petition is filed in the Regional Trial Court (Family Court) where either the petitioner or respondent has resided for at least six months.
Summons: The court issues a summons to the respondent. If the respondent cannot be found, "Service by Publication" may be used.
Collusion Investigation: The Public Prosecutor (State) conducts an investigation to ensure the parties did not "fake" the grounds or agree to the annulment just to get out of the marriage (which is prohibited).
Pre-Trial: The court identifies the issues to be resolved and explores the possibility of a settlement regarding property and custody (but not the marriage itself).
Trial: Presentation of witnesses, psychological experts (if applicable), and documentary evidence.
Judgment: The court issues a decree. If granted, the Decree of Nullity/Annulment must be registered with the Local Civil Registrar and the Philippine Statistics Authority (PSA).

5. Effects of the Decree

Once a decree is issued, the legal status of the parties and their assets changes significantly:

Status: The parties are restored to the status of "Single" and can legally remarry.
Children: * In cases of Nullity (Art. 36) or Annulment, children conceived before the decree are generally considered legitimate.
- In most other Void marriages (Art. 35, 37, 38), children are considered illegitimate, unless specific exceptions apply.
Property Relations: The absolute community of property or conjugal partnership is dissolved. Assets are liquidated and distributed according to the law or a court-approved agreement.
Support: The obligation for mutual support between spouses ceases, though support for children remains mandatory.