Animal ethics is a complex subject, and only recently the concern about the moral status and rights of non human animals, is subject of debate. In this paper I will deal mostly with the ethics in deciding euthanasia in the small animal clinical setting. My purpose is to lay out some issues about animal euthanasia, with the hope of helping veterinarians to analyze the relevant ethical concerns, as this is a field of the veterinary practice in which there are many conflicts for taking the right decision and justifying the election. Euthanasia of small companion animals is a highly stressful situation for veterinarians and may be source of ethical dilemmas. The final choice must prioritize the benefit for the patient while respecting the owner´s freedom of choice.