Canada: Significant Differences Between the Canadian & U.S. Patent Systems

Last Updated: May 27 2002
Article by Ronald D. Faggetter

While the patent laws of Canada bear many similarities to those in the United States, there are also important differences, such that the outcome of a fact scenario in Canada can be very different from the outcome of the same fact scenario in the U.S. The following discussion highlights some of the more important of these differences. This article is necessarily couched in very broad terms, and is not intended as a precise or comprehensive statement of the law in either country.

First to Invent Versus First to File

As between two independent inventors, Canada awards a patent to the first to file. In this regard, the filing date is considered to be the earliest of the actual Canadian filing date, the filing date of a priority application and an international filing date in respect of a PCT application from which the Canadian application is derived.

In contrast, subject to certain limitations, the U.S. awards a patent to the first to invent.

Inequitable Conduct (Disclosure Requirements)

In contrast to the U.S., there is no obligation on a Canadian patent applicant to disclose voluntarily all known material prior art to the Canadian Patent Office. Instead, an applicant need only respond to any requisition of the Canadian Patent Office to identify specified categories of prior art.


In Canada and the U.S., in order for a patent to issue, a patent application must be examined by an Examiner. In the U.S., examination of an application commences automatically. In Canada, examination must be explicitly requested and a government examination fee submitted. Examination may be deferred for up to five years from the Canadian filing date.

Prosecution History Estoppel

The Supreme Court of Canada has recently confirmed that, unlike the situation in the U.S., the prosecution history of an application for patent cannot be used in construing the claims of a patent.

Means Plus Function Claims

In the U.S., means plus function claims are subject of 35 USC 112(6), which provision has been interpreted by U.S. Courts as limiting the scope of such claims to the means disclosed. In Canada, no such statutory limitation exists, and means plus function claims are construed according to the "purposive construction" principles as expounded in the jurisprudence. These principles permit a construction that is literal, or that may be either broader or narrower than literal.

Continuation Practice

U.S. procedure allows for the filing of a continuation (or CIP) application which claims internal priority from a parent application at any time up to the date of issue of the parent application.

While it is possible to file a continuation or CIP-type application in Canada and claim internal priority from an earlier Canadian parent application, there are some important limitations. Any continuation or CIP-type application is only entitled to internal priority if filed within one year of the earlier of the filing date of the earliest parent application and the priority filing date. As well, any applicant-derived public disclosure made more than one year prior to filing the continuation or CIP-type application will be considered prior art.

The Law on Novelty

While both Canada and the U.S. have a one-year grace period from public disclosure of an invention, Canada’s grace period only applies to applicant-derived disclosures. The U.S. grace period, on the other hand, applies to all public disclosures, whether applicant-derived or not. Another difference is that the Canadian grace period will begin to run when there is a public disclosure anywhere in the world, while the U.S. grace period starts only where such disclosure occurs in the U.S. Further, Canada has no special on-sale bar provisions.

Maintenance Fees

Whereas U.S. maintenance fees are due only three times during the life of a U.S. patent, Canadian maintenance fees are due annually, commencing on the second anniversary of the Canadian filing date. However, Canadian maintenance fees are relatively small.Jury Trials

A jury trial for a patent matter, which is available as of right in the U.S., is not an option in the Federal Court of Canada, which hears nearly all Canadian patent infringement cases.


In most Canadian courts, including the Federal Court of Canada, an oral examination for discovery may be had as of right of only one representative of each party and of the inventor.

In contrast, in U.S. litigation, depositions may be taken from a wider group of individuals, such as potential witnesses.

Recovery for Infringement

The U.S. laws give a U.S. court the discretion to award treble damages and attorneys’ fees in the case of willful infringement. Canada has no such provision. It is, however, open to a Canadian court to award punitive damages in an egregious case. Further, in Canada, while an award of costs (including attorneys’ fees) is at the discretion of the court, costs are typically awarded to the successful party.

Damages in the U.S. are available from the date of notice of infringement. Notice can be given constructively through patent marking. In Canada no such notice is required. Further, there are no provisions for patent marking. Thus, in Canada, damages are available from the first date of infringement, subject to the statutory limitation period of six years.

In Canada, where infringement is proven, the patentee may be given the choice between an award of damages or an accounting of all of the profits made by the infringer by reason of the infringement. The accounting of profits remedy was removed from U.S. law many years ago.

Prior Rights

In Canada, if a person acquired the invention before the priority date of the patent, the person has the right to use and sell to others the specific article acquired free of the patent. This provision would, for example, protect someone who had secretly made and used a machine before the priority date of a patent on the machine. While the secret use would not destroy the novelty of the patent, the person would be free to use or sell the machine after issuance of the patent.

Recent amendments to the U.S. patent laws have added a somewhat similar provision, but one which applies only to methods of doing or conducting business.

Smart & Biggar is Canada’s largest firm practising exclusively in intellectual property and technology law. With offices in Ottawa, Toronto, Montreal, Vancouver and Edmonton, we offer a full range of intellectual property and technology law services. Related to Fetherstonhaugh through common partners, offices and personnel, we have a national and international reputation for the quality of our work and the calibre of our professionals.

The content of this article does not constitute legal advice and should not be relied on in that way. Specific advice should be sought about your specific circumstances.

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Ronald D. Faggetter
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