ARVC is a hereditary, degenerative, myocardial disease prevalent in the Boxer breed. Affected dogs can be asymptomatic with occasional ventricular premature complexes, syncopal with ventricular arrhythmias, or exhibit overt systolic dysfunction with or without evidence of congestive heart failure. In all cases, affected individuals are at increased risk for sudden cardiac death. Histologically, the disease is diagnosed by the infiltration of fat and fatty-fibrous tissue beginning in the area of the right ventricular outflow tract and progressing, from epicardium to endocardium, throughout the ventricle, with occasional involvement of the interventricular septum and left ventricular free wall. Medical management via antiarrhythmics is the only effective treatment option at this time. Many dogs respond well to therapy; however, some progress to significant systolic dysfunction, at which point long-term prognosis is poor. This case report will focus on the clinical presentation, diagnosis, treatment, and pathophysiology of the disease.