Q: Can I file a patent in Canada if it has already been filed in another country?

A: Yes, you should be able to do that. You are able to do so, if the earlier patent application is yours as well, and as long as you apply within a year of filing the earlier application.

You should be aware that Canada, like most of the world (but not like the US), has an absolute novelty requirement. This means that if you published something about your invention shortly before filing on it at the US Patent Office, you would be able to get a US patent but not a Canadian patent.

Good luck!

A: Mr. Mlynek's answer is correct but I suspect that you were not the person that filed the patent somewhere else. If that is the situation then you are not supposed to file patent applications on things that you did not invent.

Secondly, as you know of these patent applications filed somewhere else, presumably they were published and will be prior art to any subsequent filing in Canada for the same invention.

Now it is very possible that you were inspired by the published patent application that you read and have invented improvements over that invention. It is more than 100 years since the Bell patent application for the telephone was filed and people are still patenting improvements to the telephone.

You may be able to prevent people from adding your improvement but you will not prevent anyone from using the invention in the earlier filed patent application unless you have or acquire ownership of that earlier application.

If you found this answer helpful, you may want to look at my answers to other questions about patent law are available at the bottom of my profile page at https://lawyers.justia.com/lawyer/kevin-e-flynn-880338

Kevin E Flynn