Carbon dioxide stunning is the most common stunning method for slaughter of pigs in Sweden. For almost twenty years, the disadvantages of the method from an animal welfare perspective have been known. According to the Swedish Animal Protection Act, animals must be protected against unnecessary suffering - this also applies to slaughter. The law stipulates a requirement for stunning when slaughtering animals, with the aim of protecting them from suffering. At the same time, the Swedish Agency for Agriculture has issued regulations approving carbon dioxide stunning - a method that according to scientific research causes the animals suffering. The essay examines the legal status of animals, Swedish animal welfare in general, its emergence and legal development, the purpose and basic requirements of the Animal Welfare Act, as well as detailed regulations regarding slaughter both at EU level and at national level, and compares it with the Swedish Agency for Agriculture´s decision to allow carbon dioxide stunning during the slaughter of pigs. The petition aims to analyse the approval of the stunning method from a legal perspecitve, i.e. its compatibility with other welfare legislation, as well as from an animal welfare perspective, i.e. from the animals´needs and behaviour. Since the knowledge of animal welfare must be the basis for the legal cosiderations concerning Swedish animal protection, the perspectives are brought together in the assessment of whether carbon dioxide stunning should be an approved method in Sweden or not.