Also known as: parol evidence rule · parol evidence · parole evidence rule · parole evidence doctrine
Written by attorneys · grounded in primary & secondary sources — see below
A substantive rule of contract law that renders prior agreements inoperative to the extent they contradict or add to a completely integrated writing. The court determines as a preliminary matter whether an agreement is integrated and the degree of integration before applying the rule. The doctrine does not bar evidence offered to show fraud, illegality, or to interpret ambiguous terms.
Star Team contracted with Frontier Sports to buy land for a practice facility. The contract contained a merger clause and Frontier orally promised a long-term lease on an adjacent parcel for parking. After closing the deed conveyed only the main parcel. Star Team cannot enforce the oral parking promise because the merger clause and deed control post-closing rights.
Nimbus Cloud Services and PixelApps signed a subscription agreement that appeared fully integrated but left the term monthly active users undefined. PixelApps offered negotiation emails to show the parties agreed the term excluded free trial users. The court first determines whether the writing is integrated before deciding whether the emails may be used to clarify meaning.
Select any source to read its text and confirm it supports the definition.
Silver Charity conveyed its shelter building to Amy by absolute deed while simultaneously signing a side letter stating the deed secured repayment and allowed redemption within three years. Amy later refused reconveyance after tender. The court admits the side letter and board minutes to show the deed was intended only as security.
North Utilities and Union Renewable signed a forty-page integrated agreement for wind power that contained an integration clause but omitted any commitment to fund interconnection upgrades. North Utilities seeks to enforce an earlier oral promise to fund the upgrades. The integrated writing discharges the prior oral agreement.
The court decides as a preliminary question whether an agreement is integrated before applying the parol evidence rule or interpreting the writing.
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No. Evidence of fraud, illegality, or other invalidating causes remains admissible even when a writing contains a merger clause.
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Extrinsic evidence is admissible to explain the meaning of an undefined term even in a fully integrated writing because the rule does not bar interpretive use of prior negotiations.
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A merger clause together with the deed after closing limits enforcement of prior promises not reflected in the deed, subject to exceptions for fraud, mistake, or collateral agreements.
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…The Borderland of Hearsay, 39 Yale L.J. 489 (1930). [^maj-5]: Dallas County analogizes the hearsay rule to such rules as the parol evidence rule ( Patterson-Ballagh Corp. v. Byron Jackson Co. , 9 Cir., 1944, 145 F.2d 786; Long v. Morris , 3 Cir., 1942, 128 F.2d 653, 141 A.L.R. 1041), privileges ( Munzer v. Swedish American Line ,…