Patentable Inventions

Patents shall be granted for inventions in any field of technology, which are new, involve an inventive step and are susceptible of industrial application.


An invention shall be considered to be new if it does not form part of the state of the art.

Inventive Step

An invention shall be considered to involve an inventive step if, having regard to the state of the art at the filing date or the priority date, respectively, it is not obvious to a person skilled in the art.

Industrial Application

An invention shall be considered susceptible of industrial application if it can be made or used repeatedly in any branch of industry or agriculture.

Legal Protection

Legal protection for a patentable invention shall be afforded by means of a patent.

Term of Patent

The term of validity of a patent shall be 20 years from the date of filing of the application.

Fees for Maintaining Patent

Annual maintenance fees shall be paid in respect of a patent, each patent year starting from the filing date of the patent application, the first patent year starting from that date too.

Advance payment of the patent annuity for each subsequent patent year shall be effected no later than on the last day of the month, in which the preceding patent year expires. Payment may not be effected for more than one patent year.


The applicant may file a request for transformation of the patent application into an application for utility model registration . The transformed application shall preserve the filing date and the priority date of the initially filed patent application, which is deemed to be withdrawn.


Applicants with no permanent address or principle place of business in the Republic of Bulgaria shall be required to act in proceedings before the Patent Office through a local industrial property representative .