Sections 54 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.
A patent of addition protects an improvement in, or modification of, an invention that is already the subject of a patent or a pending application by the same person. Section 54 says when it can be granted, section 55 says how long it lasts and that no renewal fees are payable, and section 56 protects it from certain validity attacks. If you are filing an improvement, our patent drafting and filing team can help you decide whether it should be a patent of addition or an independent patent.
A patent of addition may be granted for an improvement or modification of the main invention if the applicant has applied for, or already holds, the main patent (s.54(1)). It cannot be granted before the main patent is granted (s.54(4)). It lasts for the remaining term of the main patent and needs no renewal fees (s.55). It cannot be refused or revoked only for lack of inventive step over the main invention, nor because it should have been an independent patent (s.56).
Amendments to know
Section 54(3) has the word "application" in two places in place of "complete specification", and sub-section (4) was substituted, both by the Patents (Amendment) Act, 2005 (from 1 January 2005). Sections 55 and 56 are printed in their original form. Neither the Tribunals Reforms Act, 2021 nor the Jan Vishwas (Amendment of Provisions) Act, 2023 changed them. Our existing guide on patents of addition is a general overview.
Section 54: the grant of a patent of addition
Sub-section (1): the improvement route
"Subject to the provisions contained in this section, where an application is made for a patent in respect of any improvement in or modification of an invention described or disclosed in the complete specification filed therefor (in this Act referred to as the 'main invention') and the applicant also applies or has applied for a patent for that invention or is the patentee in respect thereof, the Controller may, if the applicant so requests, grant the patent for the improvement or modification as a patent of addition."
Conditions in order:
- The new application is for an improvement in or modification of an invention described in a complete specification. That invention is the "main invention".
- The applicant must also apply or have applied for the main patent, or be the patentee of it. The same person must stand on both sides.
- The applicant must request the patent of addition. The Controller "may" grant; the text leaves it as a power, not a duty.
Sub-section (2): converting an independent patent
Where an improvement is already "the subject of an independent patent" and the patentee for it is also the patentee for the main invention, the Controller "may, if the patentee so requests, by order, revoke the patent for the improvement or modification and grant to the patentee a patent of addition in respect thereof, bearing the same date as the date of the patent so revoked." The patent of addition keeps the old date.
Sub-section (3): filing-date rule
"A patent shall not be granted as a patent of addition unless the date of filing of the application was the same as or later than the date of filing of the application in respect of the main invention." The improvement cannot be filed before the main application.
Sub-section (4): not before the main patent
"A patent of addition shall not be granted before grant of the patent for the main invention." The main patent must be granted first, or at the same time on the printed wording that says only "before".
Section 55: term of patents of addition
Sub-section (1): same term, no longer
"A patent of addition shall be granted for a term equal to that of the patent for the main invention, or so much thereof as has not expired, and shall remain in force during that term or until the previous cesser of the patent for the main invention and no longer."
So a patent of addition does not start its own twenty-year clock; it ends with the main patent. If the main patent lapses earlier, the patent of addition goes with it.
The proviso. "If the patent for the main invention is revoked under this Act, the court, or, as the case may be, the Controller, on request made to him by the patentee in the prescribed manner, may order that the patent of addition shall become an independent patent for the remainder of the term for the patent for the main invention and thereupon the patent shall continue in force as an independent patent accordingly." The patentee must ask, and the order is discretionary. The text speaks of revocation only; it does not mention surrender or lapse in the proviso.
Sub-section (2): fees
"No renewal fees shall be payable in respect of a patent of addition, but, if any such patent becomes an independent patent under sub-section (1), the same fees shall thereafter be payable, upon the same dates, as if the patent had been originally granted as an independent patent." The amounts are prescribed by the Patents Rules, 2003; none are given here. Renewal rules are described in the article on section 53.
Section 56: validity of patents of addition
Sub-section (1): inventive step
The grant of a patent of addition "shall not be refused, and a patent granted as a patent of addition shall not be revoked or invalidated, on the ground only that the invention claimed in the complete specification does not involve any inventive step having regard to any publication or use of":
- (a) the main invention described in its complete specification; or
- (b) any improvement or modification of the main invention described in the complete specification of a patent of addition to the main patent, or of an application for such a patent of addition.
The word "only" matters: if there are other grounds, they remain open. The section also says the validity of a patent of addition "shall not be questioned on the ground that the invention ought to have been the subject of an independent patent."
Sub-section (2): novelty
"For the removal of doubts it is hereby declared that in determining the novelty of the invention claimed in the complete specification filed in pursuance of an application for a patent of addition regard shall be had also to the complete specification in which the main invention is described." Novelty is still tested against the main specification; only the inventive step attack based on the main invention (and related additions) is shut out.
| Question | Section | Answer |
|---|---|---|
| Who may apply? | 54(1) | Applicant who has applied for, or holds, the main patent |
| Filing date | 54(3) | Same as or later than the main application |
| Grant before main patent? | 54(4) | No |
| Term | 55(1) | Equal to the main patent's remaining term |
| Renewal fees | 55(2) | None, unless it becomes independent |
| Refusal for no inventive step over main invention | 56(1) | Not on that ground only |
| Novelty tested against main specification? | 56(2) | Yes |
Illustration (invented)
Greenfield Pumps Pvt. Ltd. holds a patent on a solar-powered irrigation pump. Two years later it designs a sensor that switches the pump off when the soil is wet. This is an improvement of the main invention. Greenfield files an application for the sensor and asks for a patent of addition. Because its filing date is later than the pump application and the pump patent is granted, the Controller may grant a patent of addition for the sensor. It lasts only as long as the pump patent and has no renewal fee. If a rival argues the sensor lacks inventive step over the pump, section 56(1) bars refusal or revocation on that ground alone. If the pump patent is revoked, Greenfield may request that the sensor patent continue as an independent patent for the rest of the term; from then on renewal fees are payable.
What the sections do not say
- They give no fee, form or time for the request; "prescribed" matters are in the Rules.
- They do not say how a "main invention" with several claims is compared with the improvement.
- Section 55(1) proviso covers revocation of the main patent only.
Need help deciding between a patent of addition and a new patent?
The choice affects term, fees and risk. Our patent drafting and filing team can compare your improvement with the main patent, draft the specification and prepare the request.
Key takeaways
- A patent of addition covers an improvement or modification of the main invention and needs the same applicant or patentee.
- The filing date cannot be earlier than the main application, and the grant cannot come before the main patent.
- Its term equals the remaining term of the main patent; no renewal fees are payable unless it turns independent.
- It cannot be refused or revoked only for lack of inventive step over the main invention, but novelty is tested against the main specification too.
Read next
- Section 53: term of patent
- Section 57: amendment of application and specification before the Controller
- Patent grant and certificate: rights of the patentee
- Provisional vs complete patent specification
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.