Contributory infringement
Contributory infringement under 35 U.S.C. § 271(c) makes a seller liable for supplying a component of a patented invention — or a material or apparatus for use in a patented process — when the seller knows the component is especially made or adapted for infringing use and the component is not a staple article with substantial noninfringing uses. It is one of the two forms of indirect infringement; the other is inducement under § 271(b). Both require someone else to directly infringe.
The statute
Section 271(c) provides:
Whoever offers to sell or sells within the United States or imports into the United States a component of a patented machine, manufacture, combination or composition, or a material or apparatus for use in practicing a patented process, constituting a material part of the invention, knowing the same to be especially made or especially adapted for use in an infringement of such patent, and not a staple article or commodity of commerce suitable for substantial noninfringing use, shall be liable as a contributory infringer.
Congress enacted § 271(c) in the Patent Act of 1952 to codify the judge-made contributory infringement doctrine, which the Supreme Court had cut back in Mercoid Corp. v. Mid-Continent Investment Co., 320 U.S. 661 (1944). Section 271(d) was enacted at the same time to make clear that a patentee who controls the sale of nonstaple components does not thereby commit patent misuse. The Supreme Court read the two provisions together in Dawson Chemical Co. v. Rohm & Haas Co., 448 U.S. 176 (1980), holding that a patentee could refuse to license a patented method while selling an unpatented nonstaple chemical used only to practice it.
Elements
A patentee proving contributory infringement must establish each of the following, generally by a preponderance of the evidence:
- Direct infringement by someone. There is no contributory infringement without an underlying act of direct infringement. Aro Manufacturing Co. v. Convertible Top Replacement Co., 365 U.S. 336 (1961) (Aro I).
- A sale, offer to sell, or importation in or into the United States of a component, material, or apparatus.
- Material part of the invention. The component must be a material part of the claimed invention, not a trivial or incidental item.
- Knowledge. The seller must know that the component is especially made or adapted for use in an infringement of the patent — which requires knowledge of the patent and of the infringing use. Aro II, 377 U.S. at 488. In Global-Tech Appliances, Inc. v. SEB S.A., 563 U.S. 754 (2011), the Court relied on Aro II's reading of § 271(c) in holding that inducement requires the same knowledge, and that willful blindness can satisfy it.
- No substantial noninfringing use. The component must not be a staple article or commodity of commerce suitable for substantial noninfringing use.
Unlike inducement, contributory infringement does not require proof of an affirmative intent to encourage infringement. The knowledge element and the nonstaple requirement do that work.
The staple-article rule and substantial noninfringing uses
The staple-article exclusion is usually the decisive element. If the component has a substantial use that does not infringe, selling it is not contributory infringement, however likely it is that some buyers will infringe. The rule protects commerce in general-purpose goods: a seller of ordinary screws, chips, or chemicals is not a contributory infringer merely because some customers use them in a patented combination.
The Federal Circuit has explained that noninfringing uses are not "substantial" when they are unusual, far-fetched, illusory, impractical, occasional, aberrant, or experimental. See Vita-Mix Corp. v. Basic Holding, Inc., 581 F.3d 1317 (Fed. Cir. 2009); In re Bill of Lading Transmission & Processing System Patent Litigation, 681 F.3d 1323 (Fed. Cir. 2012) (affirming dismissal of contributory infringement claims where the complaint itself showed substantial noninfringing uses, while reinstating inducement claims).
A seller cannot avoid § 271(c) by embedding a component that has no noninfringing use inside a larger product that does. In Ricoh Co. v. Quanta Computer Inc., 550 F.3d 1325 (Fed. Cir. 2008), the court held that the inquiry focuses on the separable component specially designed to perform the patented method, not on the larger product into which it is built.
The staple-article concept later migrated to copyright law: the Supreme Court borrowed it in Sony Corp. of America v. Universal City Studios, Inc., 464 U.S. 417 (1984), to hold that selling a device capable of substantial noninfringing uses is not contributory copyright infringement.
Method claims, expired patents, and foreign assembly
Method claims
Contributory infringement can apply to a method claim. Section 271(c) expressly covers "a material or apparatus for use in practicing a patented process." The seller of an apparatus or material especially adapted to perform the patented method, with no substantial noninfringing use, can be liable when its customers perform the method.
Expired patents
There is no infringement — direct or indirect — for conduct after a patent expires. A patent owner may still sue after expiration for contributory infringement that occurred while the patent was in force, subject to the six-year limit on recovery in 35 U.S.C. § 286 and, for products, the marking and notice requirements of § 287.
Supplying components for assembly abroad
Section 271(f)(2) is the extraterritorial counterpart of § 271(c): it reaches supplying from the United States a component especially made or adapted for use in the invention, not a staple article, knowing it is so made or adapted and intending that it be combined abroad in a manner that would infringe if done here. Section 271(f)(1) separately addresses supplying all or a substantial portion of the components; in Life Technologies Corp. v. Promega Corp., 580 U.S. 140 (2017), the Court held that a single commodity component does not satisfy (f)(1).
Contributory infringement vs. inducement
- Conduct: § 271(c) reaches selling, offering, or importing a component, material, or apparatus. § 271(b) reaches any conduct that actively induces infringement — instructions, advertising, design, technical support.
- Mental state: both require knowledge of the patent and that the conduct is infringing. Inducement additionally requires specific intent to encourage infringement (DSU Medical Corp. v. JMS Co., 471 F.3d 1293 (Fed. Cir. 2006) (en banc in relevant part)).
- Product limitation: only § 271(c) has the staple-article exclusion. A product with substantial noninfringing uses can still support inducement if the seller actively encourages the infringing use.
- Defense based on belief of invalidity: under Commil USA, LLC v. Cisco Systems, Inc., 575 U.S. 632 (2015), a good-faith belief that the patent is invalid is not a defense to inducement.
Plaintiffs typically plead both theories. See induced and contributory infringement for the combined framework.
Practical notes
- Pre-suit knowledge is often the hardest element to plead. A notice letter that identifies the patent and the accused component establishes knowledge from the date of receipt; post-suit knowledge from the complaint supports liability going forward.
- Accused suppliers should document real-world noninfringing uses with customer and sales evidence; theoretical alternatives carry little weight.
- Because liability depends on direct infringement by customers, the patentee should identify the direct infringers and prove their infringing use, often with documentation, surveys, or expert testimony.
- Damages are measured under 35 U.S.C. § 284 as for any infringement. See reasonable royalty and lost profits.
Frequently asked questions
What is contributory patent infringement?
It is liability under 35 U.S.C. § 271(c) for selling, offering, or importing a material component of a patented invention, knowing it is especially made or adapted for infringing use, where the component has no substantial noninfringing use and someone directly infringes.
What is the difference between contributory and induced infringement?
Contributory infringement targets the sale of a nonstaple component; inducement targets any conduct that actively encourages infringement and requires specific intent. Both require knowledge of the patent and an underlying act of direct infringement.
Can there be contributory infringement of a method claim?
Yes. Section 271(c) covers a material or apparatus for use in practicing a patented process, so selling equipment or materials especially adapted to perform a patented method can be contributory infringement.
What is a substantial noninfringing use?
A use of the component that does not infringe and is not unusual, far-fetched, illusory, impractical, occasional, aberrant, or experimental. If such a use exists, the component is a staple article and § 271(c) does not apply.
Can you sue for contributory infringement after the patent expires?
Yes, for infringement that occurred before expiration, subject to the six-year damages limit in 35 U.S.C. § 286 and the marking and notice rules of § 287. Conduct after expiration does not infringe.
See also
- Induced and contributory infringementCombined framework for indirect liability.
- Direct infringementThe predicate act required for contributory liability.
- Patent exhaustionAuthorized sales can cut off downstream claims.
- WillfulnessKnowledge evidence often overlaps with enhanced-damages claims.
- All-elements ruleThe direct infringer must practice every limitation.
Last reviewed: October 2026