During this century the field of work for zoo veterinarians has dramatically changed. Preventive medicine at herd, group or even species level has gained importance. The therapy of single animals is no longer a priority. On the basis of recent developments progress for the future can be proposed. Effective conservation requires thinking and action by a combination of different specialists. Exchange of information at an international level will be of increasing importance. The continuing specialisation in veterinary and human medicine requires interdisciplinary co-operation. The ethics of research and medical interventions on zoo animals is of concern to the public and it is necessary to publicly advance the arguments for and against. The training of specialized zoo veterinarians should be increased.