Abstract A population survey of the genetic disease citrullinemia in the German Holsteins was made, to investigate the incidence of this genetic disease in the main dairy breed in Germany. Animals homozygous for the mutation die within the first week of life. A previous study of SMR embryos from a local herd revealed that 17% were heterozygous carriers. Semen samples were screened from 866 Holsteins, 91 Schwarzbuntes Milchrind (SMR) and 34 German Friesian bulls from German AI studs. Holstein bulls were chosen randomly from the actual German Holstein unproven AI bull stock in spring 1994, while the others represent all available bulls of the breeds in spring 1994. From these bulls, DNA samples were tested by using a modified genetic assay, which allowed a reliable diagnosis of homozygous and heterozygous animals. No citrullinemia carrier was found throughout all of the three black and white breeds in Germany, indicating no incidence of citrullinemia in the actual German Holstein population. A previous study of SMR embryos from a local herd revealed that 17% were citrullinemia carriers. There may nevertheless, be a low incidence of some heterozygous animals in the German population.