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List of Common Civil Affirmative Defenses in Colorado

Defense Law
If you have been sued, you might have a basis to raise affirmative defenses. An affirmative defense is a defense based on facts other than those supporting the plaintiff’s claim for relief, which may defeat some or all of the plaintiff’s claim. The defendant has the burden of proof to establish an affirmative defense. Most importantly, affirmative defenses must be raised in a defendant’s first response to a plaintiff’s complaint, or the defendant risks waiving those defenses.

Common Civil Affirmative Defenses

Here is a list of common affirmative defenses in Colorado. It is not an exhaustive list, and other, more specialized affirmative defenses may exist depending on the type of case–for example, employment or antitrust cases. Please note that the applicability of these defenses is case-specific and (sometimes) claim-specific, and you must have an adequate factual basis to raise an affirmative defense.

Accord and Satisfaction

Also known as “Later Contract,” this defense is specific to breach of contract claims. The plaintiff is barred from recovery if the defendant can prove that (1) the plaintiff and defendant entered into a later contract, (2) knew or should have known that the later contract canceled or changed their remaining rights and duties under the earlier contract, and (3) the defendant fully performed under the later contract.

Arbitration and Award

This affirmative defense applies where the parties agreed to submit their dispute to arbitration before an award of damages can be entered

Assumption of Risk

Assumption of risk is a form of contributory negligence (see below). This defense applies where the plaintiff voluntarily or unreasonably exposes themself to the injury or damage with knowledge or appreciation of the danger and risk involved.

Contributory/Comparative Negligence

If you’ve been sued for negligence, you can allege that the plaintiff’s own negligence contributed to the accident. If successful on a defense of comparative negligence, then the judge or jury will determine the percentage of fault attributable to the plaintiff. Any award gets reduced by that percentage. In Colorado, if the plaintiff’s fault is greater than or equal to the combined fault of the defendant(s), the plaintiff is barred from recovery altogether.

Discharge in Bankruptcy

This defense applies where an alleged debt has already been discharged in a bankruptcy action.


This affirmative defense is specific to contract claims. It applies where the defendant can show that the defendant did not enter the alleged contract under their own free will, and that the plaintiff caused the defendant’s lack of free will.


Under the doctrine of estoppel, a defendant who detrimentally changes position in reasonable  reliance on the words or conduct of the plaintiff may be excused from performance under an alleged contract.

Failure of Consideration

All contracts must be supported by consideration, which is–put simply–a bargained-for exchange of promises. A defendant seeking to defeat a contract for lack of consideration carries the burden of proving the lack thereof, and must raise it as an affirmative defense.

Failure to Mitigate Damages

A plaintiff in any civil action has the duty to take reasonable steps to mitigate their damages. For example, if a landlord sues a tenant for breaching a lease by abandoning the property, the landlord has a duty to make reasonable efforts to find a new tenant as soon as possible. If a defendant can prove that the plaintiff failed to take such reasonable steps, then the plaintiff’s award can be reduced by amounts which could have been received by the plaintiff but for such failure.

Fraud in the Inducement

In a contract action, if a defendant can show that a plaintiff induced the defendant to enter the subject contract by concealing or misrepresenting a material fact, and the defendant justifiably relied on that concealment or misrepresentation in entering the contract, the defendant can avoid liability. Bear in mind that C.R.C.P. 9 provides that all circumstances constituting fraud must be alleged with particularity.


Where a defendant to a breach of contract claim can demonstrate that the agreement was illegal, the contract is void and cannot be enforced. For example, an agreement to compensate an unlicensed real estate broker in connection with the purchase or sale of a home would be illegal, and therefore void.


Laches is an equitable concept. If a plaintiff unconscionably delays in enforcing a known right under the circumstances and a defendant relies to their detriment on such delay, the plaintiff may be barred from relief.


The affirmative defense of license argues that the defendant had permission from the plaintiff to do the alleged wrongful act. It is applicable to the use of both tangible and intangible property, as well as claims for trespass to land.


Under a defense of minority, a defendant to a breach of contract claim can be excused from performance under the alleged contract if they were 18 years of age at the time the alleged contract was formed, and if the defendant disaffirmed or rejected the contract before becoming 18 or shortly thereafter.

Negligence or Fault of Designated Nonparty

Similar to the concept of contributory negligence, a defendant’s fault for a plaintiff’s damages can be reduced if the negligence or fault of a nonparty to the case is shown to be a cause of the plaintiff’s damages. In such a case, the defendant would only be required to pay damages in an amount proportionate to their fault.

Nonuse of Safety Belt

In an auto accident, the nonuse of a safety belt by the plaintiff may be an affirmative defense. A plaintiff who did not wear a seat belt will not be entitled to damages caused by their failure to do so.


This defense is available in an action to enforce a lien. For example, if a contractor places a mechanic’s lien on a home and sues to foreclose on the lien, the contractor is barred from recovery if the defendant can demonstrate that they or someone acting on their behalf have paid an amount sufficient to satisfy the owner’s contractual and legal obligations.


Release is available where a plaintiff specifically gave up the right to pursue certain claims. This defense would be applicable if a plaintiff entered a settlement agreement, released claims against a defendant, but then sued the defendant again for those claims.

Res Judicata

Res judicata (also known as “claim preclusion”) prevents the perpetual re-litigation of the same claim or cause of action. If a defendant can show that a previous final judgment exists concerning the same subject matter, the same claims for relief, and the same parties (or parties in privity with those parties), then the claim is barred.

Statute of Frauds

In Colorado, certain contracts must be in writing to be enforceable. Specifically,:
  • Contracts where performance is rendered over a period of longer than one year;
  • Contracts relating to marriage;
  • Lease agreements for real property longer than one year;
  • Contracts for the purchase and sale of real property;
  • Contracts for the sale of goods over $500;
  • Contracts for the lease of goods in excess of $1,000;
  • Credit agreements in excess of $25,000; and
  • Contracts agreeing to pay the debt of another.

Statute of Limitations

Generally, civil claims must be brought within a certain amount of time after a plaintiff knew or should have known about the facts giving rise to the claim. The length of the limitations period depends on the claim, so it is important to seek counsel soon after learning that you might have a legal cause of action.

Unclean Hands

The doctrine of unclean hands is an affirmative defense to equitable claims. Under the doctrine, a party engaging in improper or fraudulent conduct relating in some significant way to the subject matter of the cause of action may be ineligible for equitable relief.


Waiver is the intentional relinquishment of a known right. If a plaintiff has waived their legal rights against a defendant, then they will be barred from recovering against that defendant. DISCLAIMER: This is for general informational purposes only and not furnished for purposes of offering legal advice. The best source of information for your specific matter is consulting an attorney.