Different contributions to the development and applications of genomic diagnosis methods in domestic animals are reported. DNA fingerprints were used to solve parentage disputes in different species, and to reveal leucochimerism in bovine dizygotic twins. In cattle, an embryo sexing method and a freemartinism diagnosis assay were also developed. The search for molecular markers of the MH (muscular hypertrophy) and R (rouan) bovine genes is described. Prion protein gene polymorphisms are investigated in the framework of a research on the genetics of bovine spongiform encephalopathies. The mutation responsible for the autosomal recessive lethal condition BLAD (bovine leucocyte adhesion deficiency) in Holstein cattle is found in our country, and the carries can be detected by a molecular method. The mutation responsible for the halothane sensitivity in pig can also be detected, what is done to control efficiently the introgression of the stress resistance allele in a Piétrain strain.