Dilated cardiomyopathy (DCM) is a heart disease which is often found in humans and animals. The age of onset of this progressive disease varies between 3 and 7 years of age. A juvenile form of DCM has been found in Portuguese Water Dogs and Doberman Pinscher Dogs. Some breeds such as Doberman pinscher, Newfoundland, Portuguese Water dog, Boxer, Great Dane, Cocker Spaniel and Irish Wolfhound exhibit a higher prevalence to DCM. There also seems to be a sex predisposition as male dogs are affected more often than female dogs and in Great Danes an X-linked recessive inheritance is likely. In Newfoundland and Boxer an autosomal dominant inheritance was found whereas an autosomal recessive inheritance was described in Portuguese Water Dogs. Atrial fibrillation as a cause or consequence of DCM is assumed for certain breeds. The causes of DCM are widely unknown in dogs. A genetic basis for this heart disease seems to exist. Apart from a few exceptions the mode of inheritance and the possible underlying gene mutations are not known for DCM in dogs. In humans mutations in several genes responsible for DCM have been identified. Comparative genetic analyses in dogs using genes causing DCM in men and a genome-wide scan with anonymus markers were not able to detect causative mutations or genomic regions harboring gene loci linked to DCM. The investigation of the genetic basis of canine DCM may lead to new insights into the pathogenesis of DCM and may result in new therapeutic approaches and breeding strategies.