Short answer. A contract is void when its cause, object or purpose is unlawful, when it is absolutely simulated, when the object did not exist or is outside the commerce of men, when the service is impossible, when the principal object cannot be ascertained, or when a law expressly declares it void.

What the law says

The following contracts are inexistent and void from the beginning: (1) Those whose cause, object or purpose is contrary to law, morals, good customs, public order or public policy; (2) Those which are absolutely simulated or fictitious;

Civil Code, Article 1409 — Void or Inexistent Contracts. Read the full provision →

What the law says

These contracts cannot be ratified. Neither can the right to set up the defense of illegality be waived.

Civil Code, Article 1409 — Void or Inexistent Contracts. Read the full provision →

Void means the contract never existed at all

Article 1409 of the Civil Code does not say these contracts may be cancelled. It says they are inexistent and void from the beginning. That is a stronger statement than it sounds. A void contract transfers nothing, obliges nobody and produces no rights that anyone can enforce, and it was already in that condition on the day it was signed. A court asked about it does not annul it — it simply declares what was always true. This is why the distinction matters so much in practice: nothing you do afterwards, however sincerely, repairs it.

The two categories that catch most real disputes

The first ground — a cause, object or purpose contrary to law, morals, good customs, public order or public policy — is the widest, and it reaches agreements that look ordinary on paper. An arrangement to conceal income, to defeat a creditor, or to hold property for someone the law disqualifies from owning it falls here whatever the document is titled. The second ground, absolutely simulated or fictitious contracts, catches deeds the parties never meant to take effect: a sale signed so that property appears to have changed hands while the seller keeps possession, the price and the ownership. Simulation is about intention, and intention is proved by what the parties actually did afterwards.

It cannot be ratified, and time does not cure it

Article 1409 closes with two sentences that decide most arguments about void contracts: These contracts cannot be ratified. Neither can the right to set up the defense of illegality be waived. So years of performance, part payment, a later confirmatory deed, or a clause in which both parties promise never to question the agreement, all change nothing. Either party can raise the nullity whenever the contract is invoked, and so can a person with a real interest who was never a party to it. There is no window that closes on the objection.

Void is not the same as voidable, and the difference is large

People use "void" loosely for any contract they want undone, but a contract vitiated by mistake, fraud, intimidation or lack of capacity is voidable under Article 1390, not void. A voidable contract is valid and enforceable until a court sets it aside, the action to annul it must be brought within a period fixed by law, and it can be ratified expressly or by conduct. So the first thing to establish about a bad contract is which category it sits in — that single answer determines whether you are on a deadline, whether your own past conduct has already cost you the objection, and what a court can actually order.

Cases citing this provision

These Supreme Court decisions cite the provision above. We list them so you can read them yourself; the summaries of what each decided are not ours to give.

Related provisions

Note. Statute text quoted on this page is reproduced from the official enactment and is linked to the full provision. The explanation around it is general legal information from Vivas & Nobles Law Office, not legal advice. Whether it applies to your situation depends on facts only a lawyer reviewing them can assess.