A 3–4‐week‐old, suckler, bull calf from Durham County, United Kingdom died due to congestive heart failure. Postmortem examination identified a Type C complete atrioventricular septal defect with concurrent double orifice mitral valve as the cause of the heart failure. Both atrioventricular septal defects and double orifice mitral valves have only rarely been reported in cattle, and never concurrently, to the authors’ knowledge.