Plain errors affecting substantial rights may be considered at a hearing on motion for a new trial, in the discretion of the court, though not raised in the motion or defectively raised, when the court finds that manifest injustice or miscarriage of justice has resulted therefrom.
Rule 78.08.New Trial--Plain Errors May Be Considered.
Part I · Rule 78: New Trials—After-Trial Motions—Preservation of Error · Last amended January 1, 1975 · Last verified July 22, 2026
In one sentenceRule 78.08 lets a Missouri trial court, in its discretion, consider plain errors affecting substantial rights at a hearing on a motion for new trial even though those errors were not raised in the motion or were raised defectively, when manifest injustice or a miscarriage of justice has resulted.
Full Text of Rule 78.08
Amendment History
Adopted April 10, 1974, eff. Jan. 1, 1975.
Official Comment
This is substantially the same as prior Rule 79.04 except that the reference to plain error being considered on appeal was deleted and placed in Rule 84.13(c).
Plain-English Summary
Rule 78.07 sets strict requirements for what must be included in a motion for new trial to preserve error, but Rule 78.08 provides a narrow safety valve for the trial court itself. Even when an error was not raised in the motion at all, or was raised in a defective way, the trial court may still consider it at the new-trial hearing.
That authority is not unlimited. The error must be a plain error affecting substantial rights, and the court must find that manifest injustice or a miscarriage of justice has resulted from it. Considering the error is also left to the court's discretion — the rule uses permissive language instead of requiring the court to reach out and address every unpreserved point.
The official comment explains that this rule descends from a prior rule that also addressed plain-error review on appeal, and that the appellate portion of that older rule was moved elsewhere, into Rule 84.13(c). Rule 78.08 is left to cover only plain-error consideration at the trial-court level, on a motion for new trial, while the appellate-level plain-error doctrine lives in Rule 84.13(c).
Frequently Asked Questions
What standard must an unpreserved error meet under this rule?
It must be plain error affecting substantial rights, and the court must find manifest injustice or a miscarriage of justice resulted from it.
Is the trial court required to consider unpreserved plain errors?
No. The rule leaves it to the court's discretion whether to consider such errors at the new-trial hearing.
Does this rule apply if the error was raised in the motion but poorly framed?
Yes. The rule covers errors 'not raised in the motion or defectively raised,' so a poorly framed allegation can still be considered under this standard.
Does Rule 78.08 also govern plain-error review on appeal?
No. The official comment notes that the appellate plain-error provision was moved to Rule 84.13(c), leaving this rule to address only the trial court's new-trial hearing.
How does this rule relate to Rule 78.07's preservation requirements?
Rule 78.07 sets what must ordinarily be included to preserve error; Rule 78.08 provides a limited, discretionary exception for plain errors even when Rule 78.07's requirements were not met.
Where does the discretion to grant relief under this rule get exercised?
At a hearing on a motion for new trial, since the rule is framed around that stage of the case.
Source & verification. Rule text and amendment history are
reproduced verbatim from the Missouri State & Federal Court Rules, adopted by the
Supreme Court of Missouri. Last verified July 22, 2026. ·
Official source
Also known as: plain error new trial Missourimanifest injustice standardunpreserved error new trialplain error affecting substantial rightsdiscretionary review new trial motion