Abstract
A multidisciplinary working group was formed to make recommendations for housing of macaques under laboratory conditions in the Netherlands. The group concluded that long-term individual caging leads to persistent abnormal behaviour. Therefore, individual housing is regarded as acceptable only for special reasons which counter-balance the adverse effects of isolation. Guidelines are given for developing more satisfactory social housing systems. Cages used in individual as well as social housing should meet certain spatial and other requirements to ensure a certain amount of diversion, freedom of movement and safety. Since the recommendations represent the opinion of experts in certain aspects of animal husbandry, the report can be used as a legal reference under the Animal Experiments Act.