The historical development of the use of laboratory animals runs broadly parallel with the development of western human medicine. From the latter half of the nineteenth century, after the first anaesthetics were discovered, the number of animals used for experiments showed a particularly marked increase. A number of causes of these developments are discussed. From the latter half of the twentieth century, experimental animals themselves have become a subject of investigation. The discipline of laboratory animal science is then developed. Laboratory animal science increases the reproducibility of experimental studies and contributes to the welfare of laboratory animals. An important recent development was started in teaching laboratory animal science when the Laboratory Animal Order promulgated on May 31, 1985, became operative. In this Order, the training requirements are stated, which have to be met by those taking part in animal experiments (investigators, animal technicians, experts in laboratory animal science). A particular training in laboratory animal science is made compulsory on each of these categories. The Department of Laboratory Animal Science in Utrecht has national terms of reference for university education in this field. The contents of this education is briefly discussed. Finally, a number of problems are reviewed, which are associated with testing the ethical aspects of animal experiments.