Sustainable breeding programmes are an essential part of any sustainable agricultural production system, and the management of genetic variation is a necessity to ensure sustainable animal breeding, ie. to ensure that livestock populations maintain their abilities for genetic adaptation. Next to maintaining genetic variability, a sustainable breeding programme also achieves genetic improvement, because otherwise ‘foreign’ populations will take over. Although modern animal breeding techniques, such as MOET (Multiple Ovulation and Embryo Transfer), cloning, use of genetic markers, all tend to increase the genetic gain, they endanger genetic variability. The project therefore aims at developing methods for genetic improvement that utilise and not jeopardise genetic diversity. Generally the loss of genetic diversity can be measured by the increase of the inbreeding in a population. So, methods will be developed that manage the increase of the inbreeding and at the same time enhance genetic improvement. Optimum Contribution selection has the potential for achieving this (Meuwissen, 1997), and will therefore be developed here from a theoretical selection method to a practical selection tool, which requires both theoretical and practi cal developments. The new selection tool will be implemented and tested in practical Norwegian breeding programmes for cattle, pigs and fish.