Bulgarian and EQE qualified European Patent Attorney

Bulgarian & European Trademark & Design Attorney

Established in 1993, patent bureau “K TAHTADJIEV” is one of the leading Industrial Property (IP) offices in Bulgaria, practicing Industrial property for over 35 years. Possessing qualifications such as EQE qualified European patent attorney and European Trademark Attorney, our expertise and practice spreads around Europe and globally as well. We have gained considerable experience over time teaming up and networking with globally acclaimed IP law firms and foreign multinational companies from the industry.


The bureau’s emphasis is on preparation, filing and prosecution of Bulgarian patent applications, European patent applications, European Patent Validations, European Patent Validation in Bulgaria, PCT applications, PCT national phase in Bulgaria, EURO-PCT regional phases, utility model registrations, trademark registrations and industrial design registrations, as well as the maintenance and defense of the obtained industrial property rights for Bulgarian and foreign clients. 

We are trained to offer patent prosecution advice in all traditional technical fields as well as in those of the most recent technologies from mechanics to electronics and telecommunications, from chemistry and pharmaceutics to biotechnology, from the topography of semiconductors to the patent protection of software.


We aim at attaching great importance to repeatedly analyzing and optimizing strategies in industrial property (IP) rights concerning the relationship between costs and benefits for our clients in particular. Our philosophy is that in the protection of industrial property rights, the technical qualification and concrete argumentation count above all else.


Our identification with the requirements of our clients reveals itself in detail, showing our technical competence and individual approach. We strongly believe that in the present dramatically increasing innovation trends, the “out-of-the-box” thinking in protecting IP should be high on our agenda.

M.Sc. Konstantin Tahtadjiev

  • European Patent Attorney (EQE qualified)
  • Bulgarian Patent Attorney
  • European Trademark & Design Attorney
  • Bulgarian Trademark & Design Attorney

Practice and professional experience:


M.Sc. Konstantin Tahtadjiev – junior graduated from Sofia University “St. Kliment Ohridski” with Bsc. degree in Applied Mathematics, as well as with Masters degree in Protection of information in computer systems and networks. Konstantin joined the IP agency K TAHTADJIEV in 2007 and has focused primarily on preparation, filing and prosecution of Bulgarian patent and utility model applications,  PCT applicaiton and European patent applications, European patent validations, Patent searches and strategies. He subsequently passed the exams for being entered in the list as a Bulgarian Patent, Trademark and Designs Attorney before the Bulgarian Patent Office (BPO). Konstantin has also gained extensive experience in all aspects of trademark and industrial designs cases, including trademark filing, prosecution, opposition, maintenance, searches, infringement, enforcement and strategic issues before the Bulgarian Patent Office, EUIPO and WIPO. 


In 2018, he successfully passed all EQE exams in one go and has been qualified as a European Patent Attorney before the European Patent Office (EPO). At present, Konstantin is among the minority of European Patent Attorney practitioners in Bulgaria and who has been entered in the list of the qualified European Patent Representatives before EPO by passing EQE and not listed under the “grandfather” clause.


In 2020, Konstantin has also successfully completed the European Trademark and Design Education Program (ETMD) organised by the European Union Intellectual Property Office (EUIPO) where he gained specifically qualified experience and knowledge in all procedural and litigations aspects related to European Union Trademarks and Designs before the EUIPO, General Court and European Court of Justice.


M.Sc. Konstantin Tahtadjiev is a member of the International Association for the Protection of Intellectual Property (AIPPI) and Institute of Professional Representatives before the European Patent Office (EPI)Recently elected as a Substitute member of the Council of the European Patent Institute.



  • European Patent Attorney (EQE qualified) registered under No. 9277890
  • Bulgarian Patent, Trademark and Design Attorney registered under No. 398
  • European Trademark and Design attorney registered under No. 64071




  • M.Sc. Protection of information in computer systems and networks at Sofia University BASc.
  • Applied mathematics at Sofia University “St. Kliment Ohridski” 
  • IT engineer – CISCO Academy
  • EUIPO’s Trademark and Design Education Program (ETMD)




English, Russian


IP Rising Star in Bulgaria for 2023 K TAHTADJIEV
Best Patent Lawyer in Bulgaria for 2023 K TAHTADJIEV
Best Trademark Lawyer in Bulgaria for 2023 - K TAHTADJIEV


Dipl. Eng. Kostadin Tahtadjiev

Dipl. Eng. Kostadin Tahtadjiev (†) established our patent bureau in 1993 and since then he had private practice as a Bulgarian & European Patent and Trademark Attorney. He was registered under No 1 in the list of industrial property representatives before the Bulgarian Patent Office. He was one of the founders of APIS (Association of Bulgarian industrial property representatives), former member of AIPPI and EPI.


Before starting his private practice and establishing his own IP agency in 1993, Kostadin Tahtadjiev had graduated from the Technical University of Sofia as Mechanical Engineer (Dipl. Eng.), with 17 years experience in metallurgy. He had also worked for 18 years as a patent examiner and Head of Patent Examination at the Bulgarian Patent Office.


He gained considerable experience over time teaming up and networking with globally acclaimed IP law firms and foreign multinational companies, which contributed to the good reputation of our IP agency.



EQE qualified European Patent & Trademark Attorney  |  Bulgarian Patent & Trademark Attorney

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