Short answer. Not necessarily. Article 1420 says that in a divisible contract, if the illegal terms can be separated from the legal ones, the latter may be enforced. So where the lawful parts can stand on their own apart from the illegal parts, the legal portion of your contract can still be upheld.
What the law says
if the illegal terms can be separated from the legal ones, the latter may be enforced
Civil Code, Article 1420 — Divisible Illegal Contracts. Read the full provision →
Illegality does not always sink the whole contract
The instinct that one illegal clause poisons everything is not the full picture. Article 1420 provides that In case of a divisible contract, if the illegal terms can be separated from the legal ones, the latter may be enforced. The law prefers to save what can lawfully be saved rather than strike down a bargain wholesale. So the real question is not simply whether some term is illegal, but whether the contract can be split — whether the good parts stand apart from the bad. If they can, the illegal terms fall away while the legal ones remain enforceable between you and the other party.
The contract must be divisible
Everything turns on divisibility. A contract is divisible when its obligations can be broken into distinct, independent parts, each capable of standing on its own. If the lawful undertakings do not depend on the illegal ones and can be performed separately, the court can enforce the clean portion. But if the illegal and legal terms are so intertwined that removing the illegal part would leave a distorted or meaningless agreement — one the parties would never have made — the contract is treated as a single, indivisible whole. In that case there is nothing to separate, and the illegality can bring down the entire contract.
What the rule does not do
Article 1420 does not rewrite your contract or cure the illegal terms; those terms simply cannot be enforced. It does not rescue an agreement whose very object or core purpose is unlawful, because there the illegality is not a severable side term but the heart of the deal. Nor does it apply where the parties clearly intended the contract to stand or fall as one indivisible bargain. The article offers salvage, not repair: it preserves lawful, self-standing obligations, and only those. Whether a given contract qualifies depends on how its terms are structured and how closely they are connected.
Why this matters to you
If part of your agreement is illegal, do not assume you have lost everything — or that you are fully bound. The practical task is to see whether the lawful commitments can be separated and enforced on their own. This affects what you can still demand and what you can safely disregard. Because the outcome hinges on whether the contract is divisible and how the illegal term relates to the rest, a careful reading of the specific clauses is essential. Where separation is possible, the Code lets the legal portion survive; where it is not, the illegality may control the whole.
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.
- Spouses David B. Carpo, et al. vs. Eleanor Chua, et al, G.R. No. 150773, September 30, 2005 — read the decision on LawPhil →
- La Bugal-B'laan Tribal Association, Inc., et al. vs. Victor O. Ramos, Secretary Department of Environment and National Resources, et al, G.R. No. 127882, December 1, 2004 — read the decision on LawPhil →
- Spouses Reynaldo K. Litonjua and Erlinda P. Litonjua & Phil. White House Auto Supply, Inc. vs. L & R Corp, Vicente M. Coloyan, etc, G.R. No. 130722, March 27, 2000 — read the decision on LawPhil →