Defenses to a Breach of Contract Claim in California

Last updated: November 2026

A California business sued for breach of contract can defend in two ways. It can deny an element of the claim, or it can plead an affirmative defense that defeats the claim even if the plaintiff's facts are true. The common affirmative defenses to breach of contract in California are the statute of limitations, the statute of frauds, prior breach, waiver, estoppel, impossibility, accord and satisfaction, and failure to mitigate. Kolmogorov Law, P.C. defends contract claims for businesses in Orange County, Los Angeles, and across California.

Call (909) 235-6116 or contact us online to discuss a contract claim your business needs to defend.

Two kinds of defenses to breach of contract: denials and affirmative defenses

Every contract plaintiff has to prove four things: a contract, its own performance or an excuse for not performing, the defendant's breach, and resulting damage. Knock out any one and the claim fails. That is a denial.

An affirmative defense is different. It says: even if everything in the complaint is true, I still win, because of some additional fact. California requires the answer to contain "a statement of any new matter constituting a defense," and each defense must be separately stated. (Code Civ. Proc., § 431.30, subds. (b)(2), (g).) Leave a defense out of the answer and you may lose the right to raise it later.

The job is to sort out which is which before the answer is due. Our guide to the first 30 days after being sued covers the deadline itself.

Defenses that attack whether a contract was formed

A contract requires parties capable of contracting, their consent, a lawful object, and sufficient consideration. (Civ. Code, § 1550.) If one is missing, there is nothing to breach.

Consent is the usual battleground. Apparent consent is not real or free when obtained through duress, menace, fraud, undue influence, or mistake. (Civ. Code, § 1567.) A signature obtained by a false statement about what the document says can support a defense and often a cross-complaint as well.

Then there is the writing requirement. Certain agreements are invalid unless they, or a memorandum of them, are in writing and signed by the party to be charged. The list includes an agreement that by its terms cannot be performed within a year, a lease longer than one year, and a sale of real property. (Civ. Code, § 1624, subd. (a)(1), (3).) Courts limit the statute of frauds where one side has partly performed or where the other side's fraud kept the deal from being written down. (Civ. Code, § 1623.) It still ends a surprising number of handshake claims.

Unconscionability is narrower. A court may refuse to enforce an unconscionable clause, sever it, or limit it (Civ. Code, § 1670.5, subd. (a)), but between two businesses with lawyers the defense rarely succeeds.

Defenses that excuse your performance

Suppose the contract is valid. You may still have been excused from performing.

The most common excuse is the other side's prior material breach. A party that has not performed its own obligations usually cannot demand yours. Whether the other side's failure was material enough to excuse you is a question of fact, and it decides many of these cases.

Performance may also be excused when it is prevented or delayed by the act of the other party, by operation of law, or by an irresistible superhuman cause, unless the parties expressly agreed otherwise. (Civ. Code, § 1511.) Our page on force majeure, impossibility, and frustration of purpose covers how those doctrines actually play out.

Waiver and estoppel are the quieter excuses. A party that accepts late payments for a year without objection may have waived strict timing. A party who intentionally led another to believe something true and to act on it cannot contradict it in litigation arising from that conduct. (Evid. Code, § 623.) A written contract can also be modified orally to the extent the oral agreement has been executed. (Civ. Code, § 1698, subd. (b).)

Defenses that end or shrink the claim

Some defenses do not dispute the breach at all. They dispute whether the plaintiff can still sue, or for how much.

The statute of limitations comes first. A claim on a written contract must be filed within four years. (Code Civ. Proc., § 337, subd. (a).) A claim on an oral contract gets two years. (Code Civ. Proc., § 339, subd. 1.) The clock generally starts at breach, so an old invoice dispute can be dead on arrival. Our statutes of limitations guide lists the periods for other business claims.

Accord and satisfaction says the debt was already settled, often by a check marked "payment in full" that the plaintiff cashed. The rules are specific; see our page on accord and satisfaction in California. A written release works the same way and needs no new consideration. (Civ. Code, § 1541.)

Failure to mitigate does not defeat liability, but it cuts damages. The plaintiff cannot recover losses it could have avoided with reasonable effort, and the defendant carries the burden of proving that. Our mitigation of damages page explains that burden.

How these defenses show up for business owners

Three patterns recur.

A distributor is sued by a supplier for refusing the final two shipments under a one-year supply agreement. The distributor's records show the supplier shipped nonconforming goods in month seven and never cured. Prior breach is the whole defense.

A consulting firm is sued on an alleged oral agreement to pay a five-year retainer. Nothing was signed, and the plaintiff's own emails describe the deal as "still being papered." Statute of frauds.

A commercial tenant is sued for back rent after the landlord accepted reduced payments for fourteen months and never reserved its rights. Waiver, and possibly an executed oral modification.

In each case the defense lived in documents the client already had.

What we do, and where these cases are heard

We read the contract and the correspondence, identify the defenses the facts support, and plead them so nothing is forfeited. Where the client has its own claim, we evaluate a cross-complaint. Strong defenses often support an early summary judgment motion or a negotiated walk-away.

Contract cases are heard in the Superior Court: for Orange County, usually the Central Justice Center in Santa Ana; for Los Angeles, the Stanley Mosk Courthouse. Diversity cases and cases with federal claims go to the Central District of California, in Santa Ana or Los Angeles. Our breach of contract practice page describes how we handle both sides of these disputes.

What to bring to the first meeting

Bring the complaint and proof of service, the signed contract with every amendment, the full email and text thread with the other side, invoices and payment records, and any notice of default or termination. If you think the other side breached first, bring the proof.

Frequently asked questions

What are the most common defenses to breach of contract in California?

The ones I see most are prior material breach by the plaintiff, the statute of limitations, the statute of frauds, waiver or estoppel based on the plaintiff's own conduct, impossibility, accord and satisfaction, and failure to mitigate. Which ones fit depends on the contract and the paper trail. Most cases involve two or three, not all of them.

Do affirmative defenses have to be in the answer?

Yes. California requires the answer to state any new matter constituting a defense, separately stated and tied to the cause of action it answers. (Code Civ. Proc., § 431.30, subds. (b)(2), (g).) Courts sometimes allow amendment, but an unpleaded defense can be excluded at trial. Plead what the facts support.

Can a verbal contract be enforced in California?

Often, yes. Most oral agreements are enforceable, with a two-year limitations period. (Code Civ. Proc., § 339, subd. 1.) The exceptions are the categories in the statute of frauds, such as agreements that cannot be performed within a year and sales of real property, which generally need a signed writing. (Civ. Code, § 1624, subd. (a).)

What if the other party breached first?

A prior material breach by the plaintiff usually excuses your later performance and is one of the strongest defenses available. The key word is material. A minor or already-cured failure generally does not excuse you. Document the first breach and your response to it at the time, not months later.

How long does the plaintiff have to sue me for breach of contract?

Four years on a written contract and two years on an oral one, in most cases, measured from the breach. (Code Civ. Proc., §§ 337, subd. (a), 339, subd. 1.) Some claims carry different periods, and tolling agreements can extend them. If the complaint looks late, plead the limitations defense first.

Talk to a California breach of contract attorney

If your business has been sued for breach of contract, call (909) 235-6116 or contact us online. Kolmogorov Law, P.C. is located at 327 Magnet, Irvine, CA 92618, and defends businesses in Orange County, Los Angeles, and throughout California.

This page provides general information about California law and is not legal advice. Outcomes depend on the contract, the facts, and the court.