Section 55 of the Patents Act, 1970
Term of patents of addition
Section 55 ties a patent of addition to the main patent's life, with no separate renewal fees while it stays an addition.
Official legal text
The verbatim statutory text of this provision is reproduced from the official source and checked by our legal reviewer before it is published here. Until that check is complete for this page, read the exact wording directly from the official source linked below — it is the only version that governs.
The authority is the enacted text, not this page. Where our wording and the official provision, or an applicable Gazette notification, do not match, the official material prevails.
What this section says, in plain language
A patent of addition is not a stand-alone right. Section 55 makes that concrete by fixing its life. A patent of addition remains in force for as long as the main patent remains in force, and no longer, unless it is revoked earlier. When the main patent reaches the end of its twenty-year term under Section 53, the patent of addition ends with it, however recently it was granted. An addition filed in the fifteenth year of a main patent therefore has about five years of life, not twenty.
The corresponding benefit is that no separate renewal fees are payable in respect of a patent of addition while it remains a patent of addition. The renewal fees paid on the main patent keep both alive. For a patentee filing several refinements over the years, this can make a real difference to the cost of maintaining a family of related rights.
The section then deals with the awkward case. If the main patent is revoked, the patent of addition would otherwise fall with it through no fault of its own. Section 55 allows the court or the Controller, as the case may be, on a request made by the patentee, to order that the patent of addition become an independent patent for the remainder of the term of the main patent. Once that order is made, renewal fees become payable on it, on the same footing as any other patent, and it must be maintained separately from then on.
That remainder is important. Converting an addition into an independent patent does not give it a fresh twenty-year term. It gives it the balance of the term the main patent would have had. The conversion preserves protection for the improvement; it does not extend it.
For portfolio managers the practical points are three. Track the main patent's expiry as the true expiry of every addition attached to it. Watch for revocation proceedings against the main patent and be ready to request independence for the additions. And once independence is ordered, add the newly independent patent to the renewal fee diary, because the free ride ends at that moment.
Why this section matters
Patentees holding patents of addition, licensees relying on them, and anyone valuing or auditing a portfolio that contains additions.
At the point of filing an addition, at every renewal cycle, and immediately if the main patent is challenged or revoked.
A term that matches the main patent, a fee exemption while the addition remains attached, and a right to seek independent status on revocation of the main patent.
An addition can lapse silently when the main patent is revoked, or fall for non-payment after independence is granted and nobody updates the renewal diary.
How it works in practice
When the main patent falls
A Coimbatore textile machinery firm holds a main patent on a compact ring frame drive granted in 2015, and a patent of addition on an improved lubrication arrangement granted in 2020. In 2024 a competitor succeeds in revoking the main patent on the ground of prior publication of the drive design. The lubrication arrangement was never part of that prior publication, and the firm does not want to lose it. Its counsel makes a request in the same proceeding, and the court orders that the patent of addition become an independent patent for the remainder of the term the main patent would have had, that is until 2035 rather than for a fresh twenty years. From that date the firm must start paying renewal fees on the newly independent patent, which it never had to do while it was an addition. The finance team adds it to the renewal calendar the same week, because a lapse now would undo everything the request achieved.
Simplified illustration only. Actual legal outcomes depend on the facts.
Key points to remember
- A patent of addition lasts only as long as the main patent, unless it is revoked earlier.
- No separate renewal fee is payable while a patent stays a patent of addition.
- If the main patent is revoked, the patentee may request that the addition become an independent patent.
- Independence runs only for the unexpired remainder of the main patent's term, not for a new twenty years.
- Once independent, the patent attracts renewal fees like any other patent.
- Filing an addition late in the life of a main patent gives only a short period of protection.
Common mistakes and misunderstandings
- Assuming a patent of addition granted recently has twenty years to run. It expires with the main patent.
- Expecting the conversion to independent status to happen automatically on revocation of the main patent. It has to be requested.
- Continuing to treat a converted patent as fee-free, which leads to a lapse for non-payment of renewal fees.
Connected provisions
The rules connected to a section are listed on their own because they are subordinate legislation. They cannot go beyond the Act, but they can be changed by notification without a new statute, so seeing them separately makes it easier to check whether the current procedure is still what you remember.
Forms, deadlines and fees
- A patent of addition expires on the same date as the main patent, whatever its own grant date.
- Renewal fees start to apply to a patent of addition only from the time it is ordered to become an independent patent.
Open the deadline calculator — and have every date confirmed against the current Rules before you rely on it.
This site does not carry a fee table. The First Schedule to the Patents Rules is the source, the rates vary with the applicant's category and with the mode of filing, and a figure quoted second-hand goes out of date quietly. How Indian patent fees work.
Related judgments
Court decisions shape how this provision is applied, but a summary is useful only if it is right. Every case note on this site is read by a legal reviewer before it goes live, and none has been completed for this provision so far. This section will fill in as those reviews finish. How case notes are prepared.
Questions people ask about Section 55
Do I pay renewal fees on a patent of addition?
No, not while it remains a patent of addition. The renewal fees paid on the main patent keep the addition in force as well. This changes if the main patent is revoked and the court or the Controller orders that the addition become an independent patent. From that point the addition is treated like any other patent and renewal fees become payable on it. Portfolio managers should update their renewal calendar immediately when such an order is made.
How long does a patent of addition last in India?
It lasts as long as the main patent lasts, and no longer. Because the main patent's twenty-year term runs from its own filing date, an addition filed several years later has only the remaining balance of that period. This is the main strategic cost of using the addition route. If the improvement is significant enough to stand on its own against an obviousness objection, an independent application with a fresh twenty-year term is often the better commercial choice.
What happens to my patent of addition if the main patent is revoked?
It does not automatically survive, but it does not have to be lost either. Section 55 allows the patentee to request the court or the Controller, in the same proceeding, to order that the patent of addition become an independent patent. If that order is made, the addition continues for the unexpired remainder of the term the main patent would have had, and renewal fees then become payable on it. The request has to be made, so a patentee defending a revocation action should plan for it in advance.
Is your patent of addition protected if the main patent falls?
MYCrave Consultancy reviews addition families, expiry dates and conversion requests so improvements are not lost with the parent patent.
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