Animal breeding aims at the selection of a new generation of farm animals which will fit better under the expected production circumstances. The researchprogramme of the Animal Breeding and Genetics group aims at identifying the(biological) role of genetic factors in the functioning of farm animals and the design of optimum schemes for long-term selection. In more detail, the following interrelated components can be distinguished in the programme: 1. Breeding objectives 2.cGenetic analysis 3. Genome mapping 4. Biological aspects 5. Breeding schemes Research on breeding objectives concentrates on the identification of traits and their relative importance for the functioning of the animal under different production circumstances. In order to define the desired genotype, knowledge on relevant genetic and biological relationships within the animal, the relationship between the animal and the farm environment and constraints on the production system is needed. Genetic analyses of experimental data and commercial populations are carried out to obtain insight into the impact of genetic and environmental factors on animals characteristics. The contribution of genetic factors is measured as genetic variation and genetic correlations between traits. For genome mapping, phenotypic information from animals with known pedigree is crucial. In recent years large scale experiments have been carried out in poultry, dairy cows and pigs. The design and analysis of these experiments involved both quantitative as well as molecular genetic research. Quantitative genetic research has concentrated on design of experiments and development of analytical methods that can handle multi-generation data. Tools have been developed which facilitate the application of comparative mapping in poultry and pigs.