These guidelines were developed by a group representing the Laboratory Animal Science Association. the British Association for Psychopharmacology, the British Neuroscience Association and the ESSWAP Foundation (European Courses in Whole Animal Pharmacology). They are designed to help with the process of making informed decisions about the best way to carry out studies of animal behaviour in biomedical experiments. Although the topics concentrate on laboratory research, some apply to ethological studies in the natural environment as well. Even investigators who need to comply with regulatory requirements (and so cannot modify either the choice of procedure or the design of their studies) need to be aware of the principles described in these guidelines.