In contract law, rescission is an equitable remedy which allows a contractual party to cancel the contract. Parties may rescind if they are the victims of a vitiating factor, such as misrepresentation, mistake, duress, or undue influence. Rescission is the unwinding of a transaction. This is done to bring the parties, as far as possible, back to the position in which they were before they entered into a contract (the status quo ante).

Taxonomy.

Rescission is used throughout the law in a number of different senses. The failure to draw these crucial distinctions is productive of serious confusion. Although Judicature legislation has been enacted throughout the common law world, and jurisdictions vary in their recognition of a distinct body of law known as equity, reference to the jurisdictional origins is still important for the purposes of exposition.

"Rescission" in the sense of termination. Rescission in this sense is not the focus of this article. Where a contract is terminated, obligations under the contract are only discharged prospectively; the contract is not rendered void ab initio. Rescission in the sense of termination covers two key situations:

First, where a party to a contract exercises an express right of termination, he or she is sometimes said to have exercised a right to rescind the contract.

Secondly, where a party is faced with a repudiation, the party can elect to terminate the contract; this too has often been referred to as an election to rescind.

"Rescission" at common law. Rescission at common law (as distinct from rescission in equity) is a self-help remedy: historically, the common law courts simply gave effect to the rescinding party's unequivocal election to rescind the contract. Rescission at common law is only available for fraudulent misrepresentations and duress. Rescission renders the contract void ab initio, and courts will only grant rescission under common law if the parties can be restored to their original positions prior to the formation of the contract ("restitutio in integrum"). Courts of Equity exercised a jurisdiction to effect rescission where restoring the parties to the contract to their pre-contract positions was not possible at common law.

"Rescission" in equity. Rescission is available in equity's exclusive jurisdiction in a wide range of situations. For example, where there has been an innocent but material misrepresentation, a breach of fiduciary duty, unconscionable conduct, or equitable fraud.

In court.

Rescission is an equitable remedy and is discretionary. It is used as a synonym for termination at law. A court may decline to rescind a contract if one party has affirmed the contract by his action, or a third party has acquired some rights or there has been substantial performance in implementing the contract. To improve chances of being granted rescission, parties may do well to describe those circumstances which may give rise to an entitlement to terminate, as was done in Koompahtoo Local Aboriginal Land Council v Sanpine Pty Ltd. Furthermore, because rescission is supposed to be imposed mutually upon both sides to a contract, the party seeking rescission normally must offer to give back all benefits he or she has received under the contract (an "offer of tender").

The US state of Virginia uses the term "cancellation" for equitable rescission. Furthermore, a minority of common law jurisdictions, like South Africa, use the term "rescission" for what other jurisdictions call "reversing", "overturning" or "overruling" a court judgment. In this sense, the term means to be set aside or made void, on application to the court that granted the judgment or to a higher court. Applications to rescind a judgment are usually made on the basis of error or for good cause.