Patents are country-specific and are rights limited to the borders of the issuing country. For example, a U.S. patent does not prevent infringement in any other country. Therefore, to seek protection for an invention outside the United States, a foreign filing strategy must be implemented. Many factors need to be considered when deciding where to file foreign patent applications. Some factors relate to the potential market and manufacturing centers for the invention, and other factors relate to the protectability and enforceability of the invention under the county’s intellectual property laws. Unfortunately, foreign patent protection can be quite expensive, depending on the size and complexity of the application, the need for translations, and the country or countries an applicant chooses to file.

After filing a U.S. patent application, there is a 12 month timeframe available for applying for patent protection outside the United States and claiming priority to the filing date of the U.S. application. Some potential filing strategies are to (1) file directly with the foreign countries, (2) file directly with regional patent offices, such as the European Patent Office, or (3) file an international application under the Patent Cooperation Treaty (PCT). Although PCT applications are considered "international" patent applications and are often referred to as such, there is currently no "international patent". It should be understood that a PCT application can only be used as a stepping stone for filing "national stage" or "regional stage" patent applications in a limited number of countries or regions. A complete list of countries that can be reached using a PCT application may be found here.

Thus, with regional patent applications and PCT applications, an applicant must still obtain a registration from each individual country to gain enforceable patent rights; however, regional and PCT applications can afford translation cost savings and provide additional time for an applicant to determine what countries it will ultimately seek patent rights. Specifically, a PCT application delays national stage filing costs and decisions by at least 18 months from filing the PCT application. Many applicants use this time to refine the invention, research their markets, and look for licensees or buyers. Frequently, the number of countries in which an applicant desires protection will assist in determining whether a PCT application will be more cost effective than other routes.

Because each country has its own rules for patentability of inventions, PCT patent applications should be carefully drafted to allow the various jurisdictions that may be sought after for patent protection to use claim terms that are fully supported by the originally filed description. Like the United States, many countries also have different forms of patent protection and application filing procedures that can be utilized depending on the importance of the invention and other business and legal considerations. Whatever strategy is taken for foreign patent protection, early planning is critical to success.