Eastern District of Texas Patent Rules
The Eastern District of Texas manages patent cases under its Patent Rules, cited as "P.R." and published as Appendix M to the court's Local Rules. The rules require the patentee to serve detailed infringement contentions before the initial case management conference, require the accused infringer to answer with invalidity contentions forty-five days later, and then run a fixed claim construction sequence that ends in a Markman hearing. The court's Docket Control Order sets the actual dates for each case.
How the rules fit together
The Patent Rules supplement the Federal Rules of Civil Procedure and the court's general Local Rules in cases involving claims of patent infringement or declaratory judgment of noninfringement or invalidity. The court may modify the deadlines in any case, and it routinely does so through two case-specific orders:
- The Docket Control Order, which sets every date from contentions through claim construction, expert reports, dispositive motions, pretrial, and jury selection.
- The Discovery Order, which sets initial disclosure obligations and discovery limits that apply alongside the Patent Rules.
Individual judges also issue standing orders on topics such as motion practice and page limits. Read the Patent Rules, the case orders, and the judge's standing orders together; the official versions are posted on the court's website, txed.uscourts.gov. This page describes the structure of the rules — confirm current text and deadlines there before relying on them.
P.R. 3-1: infringement contentions
Not later than ten days before the initial case management conference, the party claiming infringement must serve a "Disclosure of Asserted Claims and Infringement Contentions." It must include:
- each claim of each patent allegedly infringed, with the applicable subsection of 35 U.S.C. § 271 for each claim;
- each accused apparatus, product, device, process, method, act, or other instrumentality ("Accused Instrumentality"), identified by name or model number where known;
- a chart identifying specifically where each element of each asserted claim is found within each Accused Instrumentality — including, for means-plus-function limitations, the structure, acts, or materials that perform the claimed function;
- whether each element is claimed to be present literally or under the doctrine of equivalents;
- the priority date to which each asserted claim allegedly is entitled; and
- if the patentee will rely on its own product as embodying the claims, an identification of that product.
The chart requirement is the all-elements rule in procedural form: a limitation left uncharted is a gap the defendant will exploit. For indirect infringement, contentions should identify the direct infringement relied on and the acts of the alleged inducer or contributory infringer.
P.R. 3-2: documents accompanying the infringement contentions
With the P.R. 3-1 disclosure, the patentee produces specified categories of documents, including documents about any disclosure, sale, or offer of the claimed invention before the application date, documents evidencing conception and reduction to practice, and the file history of each asserted patent. These categories matter for the on-sale bar and priority disputes.
P.R. 3-3 and 3-4: invalidity contentions and production
Not later than forty-five days after service of the infringement contentions, each party opposing a claim of infringement serves "Invalidity Contentions." They must contain:
- the identity of each item of prior art that allegedly anticipates each asserted claim or renders it obvious, with details such as publication date, and for prior sales or public uses, the circumstances;
- whether each item anticipates or renders each claim obvious, and for obviousness, each combination relied on and the motivation to combine;
- a chart identifying where in each item of prior art each element of each asserted claim is found; and
- any grounds of invalidity based on indefiniteness, enablement, or written description under 35 U.S.C. § 112.
Under P.R. 3-4, the accused infringer produces with its invalidity contentions source code, specifications, schematics, flow charts, artwork, formulas, or other documentation sufficient to show the operation of any aspects or elements of the Accused Instrumentality identified in the infringement charts, together with a copy of the prior art identified in the invalidity contentions that does not appear in the file history.
Amending contentions (P.R. 3-6)
The P.R. 3-1 and 3-3 disclosures are treated as the parties' final contentions, subject to the amendment rules. P.R. 3-6 allows limited amendment without leave in specified circumstances tied to the court's claim construction ruling; otherwise, amendment or supplementation requires leave of court on a showing of good cause.
Courts in the district evaluate good cause with factors that include the explanation for the delay, the importance of the amendment, potential prejudice, and the availability of a continuance. Diligence is the central question: a party that sat on information it had, or could easily have obtained, will usually be held to its original contentions. The Federal Circuit approved this kind of diligence requirement in O2 Micro Int'l Ltd. v. Monolithic Power Sys., Inc., 467 F.3d 1355 (Fed. Cir. 2006), a case arising under the Northern District of California's similar rules.
P.R. 4-1 to 4-6: claim construction
Part 4 of the rules sets the claim construction sequence, keyed to service of the invalidity contentions and usually given concrete dates by the Docket Control Order:
- P.R. 4-1 — Exchange of proposed terms. Each party identifies the claim terms it contends the court should construe, including any it contends are governed by § 112(f).
- P.R. 4-2 — Exchange of preliminary constructions and extrinsic evidence. The parties exchange proposed constructions and identify supporting intrinsic and extrinsic evidence, including any expert testimony.
- P.R. 4-3 — Joint Claim Construction and Prehearing Statement. The parties file a joint statement listing agreed constructions, each side's proposed construction of the disputed terms with supporting evidence, the anticipated length of the hearing, and any witnesses.
- P.R. 4-4 — Completion of claim construction discovery. A short window for depositions of any declarants and related discovery.
- P.R. 4-5 — Claim construction briefs. The party claiming infringement files the opening brief, the opposing party responds, and the opening party replies. The parties also submit a joint claim construction chart.
- P.R. 4-6 — Claim construction hearing. The Markman hearing, scheduled subject to the court's calendar. In practice, claim construction is frequently referred to a magistrate judge in the Marshall division.
The governing law is Phillips v. AWH Corp., 415 F.3d 1303 (Fed. Cir. 2005) (en banc). See claim construction and Phillips v. AWH.
Model orders that often accompany the rules
Focusing patent claims and prior art. In 2013 the court issued a model order designed to narrow cases in stages. As originally issued, it called for the patentee to elect no more than ten claims per patent and thirty-two claims in total before claim construction, and no more than five claims per patent and sixteen in total afterward, with parallel limits on the prior art references the accused infringer may assert (twelve per patent and forty in total, then six per patent and twenty in total). Judges adopt, modify, or decline the model order case by case.
E-discovery. The court has also issued a model order on e-discovery in patent cases that limits email production and custodians absent a showing of need.
Practical notes
- The P.R. 3-1 deadline falls before the case management conference, so a patentee should have complete claim charts ready when it files. Pre-suit investigation under Rule 11 should already have produced most of the chart.
- Defendants commonly begin prior-art searching as soon as they are served: the forty-five-day window for invalidity contentions is short for a multi-patent case.
- Source code production under P.R. 3-4 is usually governed by a protective order with source code review provisions. See patent discovery.
- Trial settings in the district are comparatively firm. Slippage in contentions or claim construction rarely moves the trial date.
Frequently asked questions
When are infringement contentions due in the Eastern District of Texas?
Under P.R. 3-1, not later than ten days before the initial case management conference, unless the court sets a different date in the case.
When are invalidity contentions due under the EDTX Patent Rules?
Under P.R. 3-3, not later than forty-five days after service of the infringement contentions, unless the court orders otherwise. P.R. 3-4 document production, including materials showing how the accused product works, accompanies them.
What does EDTX P.R. 3-4 require?
The accused infringer must produce documents sufficient to show the operation of the accused aspects of its product, such as source code, specifications, and schematics, and copies of prior art cited in its invalidity contentions that are not in the patent file history.
Can infringement contentions be amended in EDTX?
Only in limited circumstances without leave, tied to the claim construction ruling under P.R. 3-6, or otherwise by court order on a showing of good cause, which turns largely on diligence.
Where can I find the official EDTX Patent Rules?
On the court's official website, txed.uscourts.gov, as Appendix M to the Local Rules. Patent Court is an independent reference and not the court's website.
See also
- Eastern District of TexasVenue, scheduling, transfer, and trial practice in the district.
- Local patent rules comparedHow EDTX compares with NDCA, Delaware, and WDTX.
- N.D. Cal. Patent Local RulesThe California rules the Texas rules drew on.
- Markman hearingsWhat happens at the P.R. 4-6 hearing.
- Patent discoveryProtective orders, source code, and ESI.
- All-elements ruleWhy every limitation must be charted.
Last reviewed: October 2026