This paper addresses the issue of the moral status of non-human animals, or the question whether sentient animals are morally considerable. The arguments for and against the moral status of animals are discussed, above all the argument from marginal cases. It is argued that sentient animals have moral status based on their having interests in their experiential well-being, but that there are degrees of moral status. Two interest-based approaches are presented and discussed: DeGrazia?s view that sentient animals have interests in continuing to live, and that their interests should be granted moral weight; and McMahan?s TRIA which similarly postulates that animals have interests and that in a given situation we should compare the human and animal interests at stake. Finally, the paper concludes that the anthropocentric approach to animal ethics should be abandoned in favour of the biocentric ethics.