What Is Federal Rule 35?

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Last Modified: October 15, 2026

What Is Federal Rule 35?

By: Perlman Defense Federal Criminal Lawyers | October 15, 2026 | Federal Defense

If you or a loved one have been sentenced in a federal criminal case, you may have come across references to Federal Rule 35. This provision falls under the Federal Rules of Criminal Procedure and gives courts a narrow path to revisit a sentence after it has already been handed down. 

Learning about how this rule operates is essential for anyone facing a federal sentence or weighing their options after one has been imposed. Below is what you should know about Rule 35 and how it could factor into your case.

What Is Rule 35(a)?

Federal Rule of Criminal Procedure 35(a) allows a federal court to correct a sentence resulting from an arithmetical, technical, or other clear error. The court generally must act within 14 days after the oral announcement of the sentence.

Rule 35(a) is narrow. It is not an opportunity to reconsider the entire case or raise every potential disagreement with the sentence. 

Because the 14-day window is so short, potential sentencing errors must be identified quickly. Once that period expires, Rule 35(a) generally cannot be used to correct the sentence.

What Is Rule 35(b)?

Rule 35(b) allows a federal court to reduce a sentence when the government files a motion stating that the defendant provided substantial assistance in investigating or prosecuting another person after sentencing.

The government generally must file the motion within one year of sentencing. However, Rule 35(b)(2) permits later motions in certain circumstances involving information that was not known, did not become useful, or whose usefulness could not reasonably have been anticipated within the first year.

A Rule 35(b) reduction is not automatic simply because a defendant cooperates with the government. The court must determine whether a reduction is appropriate after the government files the required motion.

How Does Substantial Assistance Lead to a Shorter Sentence?

One of the most important things to understand about Rule 35(b) is that the defendant cannot file this motion alone. Only the prosecution has the authority to request a sentence reduction based on cooperation. That puts the government in a powerful position and makes the quality of your assistance a critical factor.

When evaluating whether a reduction is warranted, the court will look at several considerations:

  • The significance and usefulness of the assistance
  • The truthfulness, completeness, and reliability of the information or testimony
  • The nature and extent of the assistance
  • Any injury or risk of injury resulting from the cooperation
  • The timeliness of the assistance

These factors can help the court evaluate the nature and value of the defendant's cooperation. The government’s evaluation of the assistance can also carry substantial weight.

Can Rule 35 Be Used Instead of an Appeal?

It is important not to confuse Rule 35 with the appeals process. An appeal asks a higher court to review a conviction, sentence, or other appealable ruling for legal error. Rule 35, by contrast, gives the sentencing court limited authority to correct certain clear sentencing errors or reduce a sentence based on substantial assistance.

If you believe your conviction or sentence involves issues outside Rule 35, a federal criminal defense attorney can evaluate whether an appeal or another form of post-conviction relief may be available.

Contact the Los Angeles Federal Criminal Defense Attorneys at Perlman Defense Federal Criminal Lawyers for Help Today

Federal Rule 35 applies in limited circumstances, and important deadlines can affect whether a sentence correction or reduction is available. Determining whether Rule 35(a), Rule 35(b), an appeal, or another form of post-conviction relief may apply requires reviewing the sentence and procedural history of the case.

Perlman Defense Federal Criminal Lawyers can review your case and explain your legal options after a federal sentence has been imposed. Contact us today to schedule a free consultation with a Los Angeles federal criminal defense lawyer.

Perlman Defense Federal Criminal Lawyers
1601 Vine St Suite 747, Los Angeles, CA 90028
(747) 373-0477
Available 24/7

Perlman Defense Federal Criminal Lawyers - Los Angeles, CA Office
Daniel Perlman
CRIMINAL DEFENSE ATTORNEY

Daniel R. Perlman, the founding attorney at Perlman Defense Federal Criminal Lawyers, leverages his extensive background as a former prosecutor to provide superior defense strategies for clients across federal courtrooms. Earning his Juris Doctor from the Catholic University of America's Columbus School of Law, he first honed his legal skills with the Maryland State’s Attorney’s Office. 

This diverse experience enables him to advocate effectively, understanding prosecution tactics intimately, which he expertly counters in defense of his clients. With a profound commitment to justice, Daniel leads his team in tackling complex federal cases, from white-collar crimes to violent offenses, ensuring the highest level of defense through every phase of the criminal process.

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