A 12-year-old girl affected by idiopathic dilated cardiomyopathy and renal failure was referred to our institution for cardiac transplantation. A simultaneous heart-kidney transplantation from the same donor was decided. The immunosuppression schedule consisted of azathioprine, antithymocyte globulin, steroids, and cyclosporine. At a follow-up visit at 24 months after transplantation, no episodes of heart or kidney rejection had occurred and cardiac and renal function were good. Concomitant failure of heart and kidney is well known in the literature, but it appears to be more frequent in adult as compared with the pediatric population. This is the first case of combined heart and kidney transplantation in a child. Because of the successful outcome and good follow-up, the number of combined organ transplantations will most likely increase in the future.