Achondroplastic dwarfism is a rare hereditary metabolic disorder associated with a higher incidence of cardiovascular disease. There are few epidemiological data and surgical experience of rheumatic valvular disease in this population. This report is the only one to date on mitral replacement in an achondroplastic dwarfism. In addition, our approach involves placing the mechanical aortic valve prosthesis upside down in the mitral position. The 10-year results show benefits, but intraoperative management, valve type, and anticoagulation regimen are real challenges.