The clinical signs and symptoms, radiographic and echocardiographic findings, and the results of cardiac post-mortem and histopathological examination of a 1-year-old female European shorthair cat with a double-chambered right ventricle (DCRV), small ventricular septal defect, and double caudal vena cava are described. A review of the literature is given with respect to the symptoms, diagnostic techniques, and therapy of DCRV in the cat. DCRV is a rare congenital defect in which stenosis inside the right ventricle causes symptoms similar to those seen in pulmonary stenosis. A diagnosis can be made by echocardiography. Little is known about its natural history and prognosis. Medical treatment, balloon dilatation, and surgery have been used to treat this defect with variable outcome. A double caudal vena cava is not clinically relevant.