Northern District of California Patent Local Rules
The Northern District of California's Patent Local Rules were the first modern set of local patent rules and remain the template most other districts have borrowed. They require infringement contentions fourteen days after the initial case management conference, invalidity contentions forty-five days after that, and a claim construction sequence in which the parties may ask the court to construe no more than ten of the most significant disputed terms without leave.
Structure of the rules
The Patent Local Rules apply to civil actions alleging infringement of a utility patent or seeking a declaratory judgment that a utility patent is not infringed, invalid, or unenforceable. They are organized in four parts: scope and construction (Part 1), general provisions including the initial case management conference (Part 2), patent disclosures (Part 3), and claim construction proceedings (Part 4). The court may accelerate, extend, or eliminate the deadlines in a particular case, and individual judges issue standing orders that supplement them.
The rules were first adopted around 2000 and have been amended several times. The official text is posted at cand.uscourts.gov; this page summarizes the structure, and the current text controls.
Patent L.R. 2-1: the initial case management conference
Beyond the topics required by Rule 26(f), the parties must meet and confer about patent-specific matters: proposed modifications of the deadlines in the Patent Local Rules, the scope and timing of any claim construction discovery and damages discovery, the format of the claim construction hearing (including whether live testimony will be offered), and how the parties intend to educate the court on the technology. Many judges in the district hold a technology tutorial before the Markman hearing.
Patent L.R. 3-1 to 3-5: contentions and accompanying documents
Patent L.R. 3-1 — infringement contentions
Not later than fourteen days after the initial case management conference, the party claiming infringement serves its "Disclosure of Asserted Claims and Infringement Contentions," including each asserted claim and the applicable subsection of 35 U.S.C. § 271; each accused instrumentality; a chart identifying specifically where and how each limitation of each asserted claim is found in each accused instrumentality; for indirect infringement, the direct infringement relied on and the acts of the alleged indirect infringer; whether each limitation is met literally or under the doctrine of equivalents; the priority date claimed for each asserted claim; any of the patentee's own products that practice the claims; and the basis for any allegation of willful infringement.
Patent L.R. 3-2 — documents accompanying infringement contentions
The patentee produces documents about pre-filing disclosures, sales, and offers of the claimed invention; documents evidencing conception and reduction to practice; the file history of each asserted patent; documents evidencing ownership; and documents sufficient to show the operation of any of its own products it says practice the claims.
Patent L.R. 3-3 — invalidity contentions
Not later than forty-five days after service of the infringement contentions, the party opposing infringement serves invalidity contentions identifying each item of prior art relied on, whether it anticipates or renders each claim obvious (with each combination and the motivation to combine), a chart showing where each limitation is found in each item, and any grounds of invalidity based on § 101, indefiniteness under § 112(b), or enablement or written description under § 112(a).
Patent L.R. 3-4 — documents accompanying invalidity contentions
The accused infringer produces source code, specifications, schematics, flow charts, formulas, or other documentation sufficient to show the operation of the accused aspects of its instrumentalities, and copies of prior art not in the file history.
Patent L.R. 3-5 — declaratory judgment actions
Adjusts the sequence when a case begins as a declaratory judgment action. The infringement-contention rules do not apply until a party actually asserts infringement; if no infringement claim is made, the party seeking a declaration of invalidity serves its invalidity contentions and accompanying documents on a deadline keyed to the opposing party's answer.
Patent L.R. 3-6: amendment only for good cause
Contentions may be amended only by order of the court upon a timely showing of good cause. The rule gives non-exhaustive examples of circumstances that may support good cause absent undue prejudice to the other side: a claim construction by the court different from that proposed by the party seeking amendment; recent discovery of material prior art despite an earlier diligent search; and recent discovery of nonpublic information about the accused instrumentality that was not discovered, despite diligent efforts, before the infringement contentions were served.
In O2 Micro Int'l Ltd. v. Monolithic Power Sys., Inc., 467 F.3d 1355 (Fed. Cir. 2006), the Federal Circuit upheld this regime, holding that good cause requires a showing of diligence and that the rules are designed to require parties to crystallize their theories early.
Advice of counsel and damages contentions
Patent L.R. 3-7 — advice of counsel. A party that will rely on an opinion of counsel as part of a defense to a claim of willful infringement must make the related production and disclosures by a deadline keyed to the court's claim construction ruling. Choosing to rely on the opinion has privilege-waiver consequences that should be evaluated early.
Patent L.R. 3-8 and 3-9 — damages contentions. Later amendments added damages contentions: the party asserting infringement identifies each category of damages sought and its theories of recovery, and the opposing party responds. These disclosures preview the reasonable royalty and lost profits theories well before expert reports.
Patent L.R. 4-1 to 4-7: claim construction
- Patent L.R. 4-1 — exchange of proposed terms (fourteen days after service of the invalidity contentions): each party identifies terms it contends should be construed and any it contends are governed by § 112(f).
- Patent L.R. 4-2 — exchange of preliminary constructions and extrinsic evidence (twenty-one days after the 4-1 exchange), including any expert testimony.
- Patent L.R. 4-3 — Joint Claim Construction and Prehearing Statement (sixty days after service of the invalidity contentions): agreed constructions, each side's proposals, and an identification of the terms whose construction will be most significant to resolution of the case, limited to ten absent leave, flagging any term said to be case- or claim-dispositive.
- Patent L.R. 4-4 — completion of claim construction discovery (thirty days after the joint statement).
- Patent L.R. 4-5 — briefing: the party claiming infringement files the opening brief forty-five days after the joint statement; the response follows fourteen days later and the reply seven days after that.
- Patent L.R. 4-6 — claim construction hearing, subject to the court's convenience, about two weeks after the reply brief.
- Patent L.R. 4-7 — good-faith participation: failure to participate in good faith in the joint statement process can support sanctions.
These are the default intervals; the case management order frequently changes them. See Markman hearings and claim construction.
Practical notes
- The ten-term limit forces early prioritization. Parties often reach agreement on many terms to stay within it, or seek leave with a specific explanation of why more terms are needed.
- Judges in the district have been receptive to stays pending inter partes review, particularly early in a case. See Northern District of California.
- The court publishes model protective orders, including one for highly sensitive confidential information and source code. See patent discovery.
- Check each judge's standing order for page limits, tutorial practice, and hearing format.
Frequently asked questions
When are infringement contentions due under the N.D. Cal. Patent Local Rules?
Under Patent L.R. 3-1, fourteen days after the initial case management conference, unless the court orders otherwise.
When are invalidity contentions due in the Northern District of California?
Under Patent L.R. 3-3, forty-five days after service of the infringement contentions, accompanied by the document production required by Patent L.R. 3-4.
How many claim terms can be construed under the N.D. Cal. rules?
Patent L.R. 4-3 limits the joint claim construction statement to the ten terms most significant to resolving the case, absent leave of court for good cause.
What counts as good cause to amend contentions under Patent L.R. 3-6?
Examples in the rule include an unexpected claim construction ruling, recent discovery of material prior art despite a diligent search, and recent discovery of nonpublic information about the accused product. Diligence is required.
See also
- Northern District of CaliforniaPatent practice in San Francisco, Oakland, and San Jose.
- Local patent rules comparedHow the California rules compare with EDTX, Delaware, and WDTX.
- Eastern District of Texas Patent RulesThe Texas adaptation of the California model.
- Markman hearingsWhat happens at the Patent L.R. 4-6 hearing.
- Patent discoveryContentions, protective orders, and source code review.
Last reviewed: October 2026