Percutaneous placement of transcatheter heart valves for treatment of degenerated surgical valves in the aortic and mitral position is an emerging therapy for selected high-risk patients. Here we describe in detail the first case in the literature of a patient (female, 72 years old, log EuroSCORE 22.9%) with a degenerated biological mitral prosthesis which was successfully treated by transapical implantation of a Lotus valve. The case described demonstrates the very controlled feasibility of valve-in-valve treatment for a degenerated mitral bioprosthesis with a mechanically expanding Lotus valve.