Dilated cardiomyopathy (DCM), a primary heart muscle disorder characterized by poor cardiac function, is inherited in the Doberman Pinscher. Therapy for DCM does not cure or even successfully control the clinical signs. The inability to control the disease has led to increased interest in disease prevention. Prevention will likely be achieved through careful selection of unaffected dogs for breeding. However, since DCM is often not apparent until later in the adult life of the dog, many dogs are selected for breeding before they are found to be affected. A blood test that could identify affected animals before they are used for breeding would greatly decrease the prevalence of DCM. The study proposed here is a continuation of a study funded by the AKC CHF that recruited and screened families of Doberman Pinschers with DCM. Pedigrees and DNA samples have been collected. Genetic analysis is now being performed on three families of Doberman Pinschers with DCM. Genetic markers will be evaluated to determine if they are associated with the development of DCM in the Doberman Pinscher. The identification of a genetic marker linked to DCM will be the first step in the development of a screening blood test.