The thesis investigates the overlap between trademark and patent law and the extent thereof and whether the overlap poses a threat to competition. The first part of the thesis concentrates on the legislation on the matter and the relevant case-law, the second part investigates the possibility of registering patented subject-matter as trademarks constituting a competition infringement. Both the registration in itself and the follow-on conduct of the proprietor amounting to an infringement are explored. The thesis is limited to article 102 TFEU perspective.