Section 27 Mistake of Fact

• Library: Remedies 2006

Either a mutual or a unilateral mistake can justify the equitable remedy of rescission. The mistake must be a mistake as to fact. A mistake as to law will not justify a rescission. In re Estate of Hysinger, 785 S.W.2d 619, 624 (Mo. App. E.D. 1990). To justify rescission, “the mistake must relate to the existence or non-existence of a fact, past or present, material to the agreement and not to a future contingency.” Id.

Historically, a mutual mistake of a material fact justified rescission or cancellation when both parties suffered the same misconception and the mistake was a common one that neither party intended. Id. The mistake must have concerned a vital part of the agreement, such that the parties never actually agreed. Frederich v. Union Elec. Light & Power Co., 82 S.W.2d 79, 86 (Mo. 1935); Miller v. Haberman, 224 S.W.2d 1002, 1006 (Mo. 1949). And the mistake must be shown by clear and convincing evidence. In re Estate of Hysinger, 785 S.W.2d at 624.

A unilateral mistake can form the basis of rescission if one party suffers from a misconception or mistake and the other party knows...