In this thesis, the development of genetically uniform strains of common carp, Cyprinus carpio L. is described. As in research on mammals, the use of genetically uniform fish could increase the quality (replicability, reproducability and repeatability) of experiments. Inbreeding was done by gynogenetic and androgenetic reproduction. With these methods, fully homozygous. offspring are produced in only one generation. The principle of these reproduction techniques is to eliminate the genetic contribution of one of the parents by (UV) irradiating the sexual products, followed by artificially inducing diploidy by physical shocks in the developing zygotes. Inbred strains, congenic strains and F1 hybrids were produced. Congenic strains were used to study sex determination in carp. Inbred strains and F1 hybrids were used to study the genetic control of gonad development after a quantitative genetic model had been developed to facilitate estimation of genetic variance. We show that genetically uniform carp strains are suitable as experimental animal model in genetic research and in bioassays (toxicological research). It is obvious that other research areas could also profit from genetically uniform carp strains.