Sections 105 explained: this guide covers what it means, who it applies to, the step-by-step process, documents required, fees, due dates and penalties in India — so you can stay compliant with confidence and avoid costly mistakes.
Two sections protect a business that is under a patent cloud. Section 105 lets a person sue for a declaration that his process or article does not, or would not, infringe a claim of a patent, even if the patentee has made no assertion, after first asking in writing for an acknowledgment and being refused. Section 106 lets a person aggrieved by threats of infringement proceedings sue for a declaration that the threats are unjustifiable, an injunction and damages, unless the defendant proves infringement. If you have received a threat or want clarity before launching a product, our legal dispute resolution team can advise.
Section 105: any person may sue the patentee or exclusive licensee for a declaration of non-infringement, even without a threat, if he first applied in writing for a written acknowledgment with full particulars and the patentee refused or neglected. The plaintiff usually pays all parties' costs, and the validity of the claim cannot be questioned. Section 106: a person aggrieved by threats of infringement proceedings, by circulars, advertisements or communications, may sue for a declaration, injunction and damages; the court may grant them unless the defendant proves infringement of a claim not shown to be invalid. A mere notification of the existence of a patent is not a threat.
Amendments to know
In section 105(4), the words "after the publication of grant of a patent" were substituted by the Patents (Amendment) Act, 2005 (from 1 January 2005). Section 106 is printed with a footnote on the word "existence" in the Explanation. The Tribunals Reforms Act, 2021 and the Jan Vishwas (Amendment of Provisions) Act, 2023 did not change either section. Both suits must be instituted in a court not inferior to a district court having jurisdiction (section 104); see our article on section 104. For what infringement itself involves, see our guide on what constitutes patent infringement and how to sue.
Section 105: declaration of non-infringement
Sub-section (1): the suit and its conditions
"Notwithstanding anything contained in section 34 of the Specific Relief Act, 1963 (47 of 1963), any person may institute a suit for a declaration that the use by him of any process, or the making, use or sale of any article by him does not, or would not, constitute an infringement of a claim of a patent against the patentee or the holder of an exclusive licence under the patent, notwithstanding that no assertion to the contrary has been made by the patentee or the licensee, if it is shown—"
- (a) "that the plaintiff has applied in writing to the patentee or exclusive licensee for a written acknowledgment to the effect of the declaration claimed and has furnished him with full particulars in writing of the process or article in question; and"
- (b) "that the patentee or licensee has refused or neglected to give such an acknowledgment."
| Element | Text |
|---|---|
| Who can sue | "Any person" |
| Against whom | The patentee or the holder of an exclusive licence |
| What is sought | A declaration that his use of a process, or making, use or sale of an article, does not or would not infringe a claim |
| Is a threat needed? | No: "notwithstanding that no assertion to the contrary has been made" |
| Condition (a) | Written application for a written acknowledgment, with full particulars in writing of the process or article |
| Condition (b) | Refusal or neglect to give the acknowledgment |
Both conditions must be shown (joined by "and"). The suit is available "notwithstanding anything contained in section 34 of the Specific Relief Act, 1963", the general law on declaratory suits. The text says the declaration may be sought about conduct that "does not, or would not" infringe, so it covers a planned product as well as an existing one.
Sub-section (2): costs
"The costs of all parties in a suit for a declaration brought by virtue of this section shall, unless for special reasons the court thinks fit to order otherwise, be paid by the plaintiff." The default is that the plaintiff bears the costs of all parties.
Sub-section (3): validity not in question
"The validity of a claim of the specification of a patent shall not be called in question in a suit for a declaration brought by virtue of this section, and accordingly the making or refusal of such a declaration in the case of a patent shall not be deemed to imply that the patent is valid or invalid." The suit is only about infringement. A declaration does not say the patent is valid.
Sub-section (4): timing
"A suit for a declaration may be brought by virtue of this section at any time after the publication of grant of a patent, and references in this section to the patentee shall be construed accordingly." The suit cannot be brought before the publication of grant.
Section 106: groundless threats
Sub-section (1): who can sue and for what
"Where any person (whether entitled to or interested in a patent or an application for a patent or not) threatens any other person by circulars or advertisements or by communications, oral or in writing addressed to that or any other person, with proceedings for infringement of a patent, any person aggrieved thereby may bring a suit against him praying for the following reliefs, that is to say—"
- (a) "a declaration to the effect that the threats are unjustifiable;"
- (b) "an injunction against the continuance of the threats; and"
- (c) "such damages, if any, as he has sustained thereby."
Note the width: the person threatening need not be entitled to or interested in a patent or application; the threat may be by circulars, advertisements or communications, oral or written, addressed to the person or to anyone else; and "any person aggrieved" may sue, not only the person threatened.
Sub-section (2): the defence of proving infringement
"Unless in such suit the defendant proves that the acts in respect of which the proceedings were threatened constitute or, if done, would constitute, an infringement of a patent or of rights arising from the publication of a complete specification in respect of a claim of the specification not shown by the plaintiff to be invalid, the court may grant to the plaintiff all or any of the reliefs prayed for."
So the defendant carries the burden of proving infringement. If he cannot, the court "may" grant all or any of the three reliefs. A plaintiff who shows the claim to be invalid can answer the defence.
Explanation
"A mere notification of the existence of a patent does not constitute a threat of proceeding within the meaning of this section." Telling a trader that a patent exists is not itself a threat. A message that goes further, by warning of proceedings, may be.
The two sections compared
| Point | Section 105 | Section 106 |
|---|---|---|
| Purpose | Declaration that use does not or would not infringe | Relief against unjustifiable threats |
| Against | Patentee or exclusive licensee | The person who threatens |
| Needs a threat? | No | Yes: a threat of infringement proceedings |
| Pre-condition | Written application for acknowledgment, refusal or neglect | None; the person must be "aggrieved" |
| Burden | Plaintiff shows conditions | Defendant must prove infringement to defeat the reliefs |
| Reliefs | Declaration | Declaration, injunction, damages |
| Costs | Plaintiff pays all parties unless special reasons | Not stated |
| Validity | Cannot be questioned | The claim must be "not shown by the plaintiff to be invalid" |
Illustration (invented)
Meghna Controls Pvt. Ltd. plans to launch a motor starter and learns that Voltix Ltd. holds a patent that might read on it. Meghna applies in writing to Voltix for a written acknowledgment that the starter does not infringe, and furnishes full written particulars. Voltix neglects to reply. Meghna may sue under section 105 for a declaration. It will ordinarily bear all parties' costs, and the court will not decide validity.
Separately, Voltix emails Meghna's dealers that it will "sue anyone who stocks the starter". Meghna sues under section 106 for a declaration that the threats are unjustifiable, an injunction and damages. Unless Voltix proves that the starter infringes a claim not shown by Meghna to be invalid, the court may grant the reliefs. If Voltix had only written that "Patent No. X exists", the Explanation says that mere notification is not a threat.
What the sections do not say
- No time within which the patentee must reply to the written application.
- No definition of "full particulars" or "unjustifiable".
- No measure of damages.
- Section 106 does not say whether the Controller or patent agents can be sued for a threat.
- Section 105(2) does not say what "special reasons" are.
Need help with a threat letter or a launch clearance?
A written request for acknowledgment, or a suit over threats, needs careful drafting and good evidence. Our legal dispute resolution team can prepare the application to the patentee, advise on the claim, and file or defend either suit.
Key takeaways
- Section 105 allows a suit for a declaration of non-infringement, even without a threat, after a written request for acknowledgment with full particulars is refused or neglected.
- The plaintiff ordinarily pays all parties' costs in a section 105 suit, and validity cannot be questioned.
- Section 106 allows a person aggrieved by threats of infringement proceedings to seek a declaration, an injunction and damages.
- The defendant in a section 106 suit must prove infringement of a claim not shown to be invalid to defeat the reliefs.
- A mere notification of the existence of a patent is not a threat.
Read next
- Section 107: defences in suit for infringement
- Section 104A: burden of proof in suits concerning infringement
- Patent infringement suit: jurisdiction and process
- Defences to patent infringement: invalidity, prior use, exhaustion
Disclaimer: Based on the Patents Act, 1970 as amended up to the Jan Vishwas (Amendment of Provisions) Act, 2023, as consulted on 1 October 2026. Forms, fees and time limits under the Patents Rules, 2003 change from time to time and are not covered here. This article is general information, not legal advice; check the official text before acting.