It is believed widely, and with good reason, that some other members of the animal kingdom, like us, have feelings (associated with brain states induced by various sensory inputs and cognitive processes) which can be pleasant or unpleasant. Associated with the strengthening scientific foundations for this belief, there has been growing consensus around the world that we have a moral responsibility, in all of our dealings and interactions with sentient animals, to take account of their feelings. This has led to widespread re-evaluation, in recent years, of the nature of our interactions with other animals. However, assessment of the feelings of animals — the quality of their lives — remains a great challenge for veterinarians and others involved with their management. The fundamental difficulty is that whilst judgements about management or treatment often have to be made on the basis of our inferences of how they feel (ie of the feelings they consciously experience), a subjective step cannot be avoided in making these inferences. We cannot know how other animals feel but can only infer this based on our knowledge of the animal and on our own experiences of feelings. This inevitable ‘gap’ in objective deductions about feelings is often wide enough that people can reach radically different conclusions when judging an animal's quality of life. Opinions thus often differ regarding the point at which it becomes kinder to euthanase an animal than not to do so, the point at which it becomes kinder not to undertake a potentially painful therapeutic intervention than to do so, and where the balance lies when animal welfare costs are being ‘weighed’ against some benefit of their use for humans (eg as laboratory, farm or companion animals). The aim of this meeting is to discuss if and how science has helped in developing reasoned approaches to these dilemmas, and to consider the need for further research, education, and policy development.