The thesis is devoted to a complex research of international legal standards of animal welfare. The author defined the basic definitions which are used by international law instruments regarding the treatment of animals; outlined a difference between the definitions of international standard, international law standard, international legal standard, and provided author definition of international law standards of animal welfare, pointing out that it is international law norms that reinforce the obligations of the States to ensure minimum of animal welfare through their implementation in national legislation; investigated the value of international law standards of the welfare of the various categories of animals (farm and laboratory animals, companion animals), examining that international law standards common to all animal species are: standards of maintenance and care, standards of transportation, standards of humane treatment of animals, particularly during the procedure of killing (or slaughter); identified differences in normative content between the definitions of "animal welfare" and "animal well-being", where "welfare" means the overall quality of life of the animal, estimated by the psychological, emotional, physical condition of an individual animal, as well as satisfactory material and technical conditions of maintenance and care in accordance with international law standards. "Animal well-being" is the current state of the animal, estimated by satisfactory material and technical conditions of maintenance and care of an individual animal, as well as its psychological, emotional, physical condition of the animal at a concrete period of time; studied the evolution and formation of international law standards of animal welfare by identifying key milestones in the development of international law standards of animal welfare. During the research it was found the legal content of international law standards of animal welfare of different animal categories, namely farm, laboratory, companion animals. It was determined the crucial role in the formation and implementation of universal international law standards of animal welfare of the international intergovernmental organizations, such as the World Organization for Animal Health (OIE), FAO in collaboration with WHO (in particular in respect of the Commission of "Codex Alimentarius"). Implementation geography in the national laws of international law standards of animal welfare developed by the OIE, FAO/WHO, WTO, etc. gave the reason to define these standards as universal international law standards of animal welfare.
