Abstract: The subject of this research is the systematization and analysis of different opinions of the countries that stood at the origins of electrical telegraphy (Russia, England, Germany, United States) regarding the question of who invented an electrical telegraph. The lower boundary of the period under consideration is the time of the emergence of first electrical telegraphs (1830’s); the upper boundary – is the time of completion of the most bitter priority conflicts (1850’s). On each of the four countries, the author analyzes value judgments of the key experts; determines the priority discrepancies, both international and domestic. The scientific novelty consists in the comprehensive character of studying priority discrepancies pertaining to electrical telegraphy and determined patterns in the nature of ambiguous priority assessments. The desire to defend prestige or gain commercial profit are the key reasons for priority discrepancies, The first reason serves as the motive for scientific disputes; the second one – for conflicts and litigations between the self-professed inventors. The opinion of all indicated countries on the priority in electrical telegraphy was based on the different understanding of the term “priority”. The Russians adhered to formal interpretation of priority (the pioneer is considered the person who patented or declared an invention) and defended the priority of Schilling. The countries that succeeded at the stage of proliferation of an invention, tended to consider the invention itself as a prehistory. The research results as an example of scientifically justified explanation of the existence of priority contests may be used for popularization of the national scientific and technological achievements in mass media, museum and educational activities.