Short answer. Three, and all three must be present at once: consent of the contracting parties, an object certain which is the subject matter of the contract, and a cause of the obligation. If any one of them is missing the agreement is not merely defective — in law, no contract ever existed.

What the law says

There is no contract unless the following requisites concur: (1) Consent of the contracting parties; (2) Object certain which is the subject matter of the contract; (3) Cause of the obligation which is established.

Civil Code, Article 1318 — Essential Requisites of a Contract. Read the full provision →

The word doing the work is "concur"

Article 1318 of the Civil Code is short and absolute: There is no contract unless the following requisites concur — consent, object and cause. They must exist together, at the moment the parties come to terms, not one after another over the following months. This is also why a signature is not what creates a contract. The signed page is evidence that consent was given; it is not the consent itself. An arrangement that was never reduced to writing is still a contract if the three requisites were there, because Article 1356 makes agreements binding in whatever form they may have been entered into.

Consent means a real meeting of minds

Consent is the requisite that fails most often in practice, and rarely because someone refused outright. It fails because the parties never agreed on the same thing. Article 1319 requires an offer that is certain and an acceptance that is absolute, so a reply that changes the price, the date or the quantity is a counter-offer rather than a yes. Consent also fails where the person giving it lacked capacity, or gave it under mistake, violence, intimidation, undue influence or fraud. That kind of contract is not void from the start; it exists and binds until a court annuls it.

Object and cause: what is being given, and why

The object is the thing, right or service the contract is about, and it must be an object certain — determinate, or at least determinable from the contract itself without a fresh agreement. A promise to sell "some land in the province" identifies nothing. The cause is the reason the party bound himself: for a sale it is the price, for a donation it is the giver's liberality. The two are commonly confused. The object of a loan is the money; the cause is the borrower's obligation to repay. A contract can have a perfectly lawful object and still fail on an unlawful cause.

What actually turns on a missing requisite

A contract missing a requisite is void under Article 1409, and void is a harder result than most people expect. It cannot be ratified by later conduct, it does not become good with the passage of time, and either party can raise its invalidity as a defence whenever it is sued on. If you are worried about an agreement you have already begun performing, the questions worth answering first are concrete: what exactly was agreed, who agreed it, what is the thing being transferred, and what each side is getting. Those four answers usually settle whether there is a contract at all.

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.