Mannose-binding lectin (MBL) is a serum protein of the innate immune system. MBL enhances opsonophagocytosis by binding to carbohydrates expressed by multiple pathogens. MBL deficiency is due to polymorphisms in the structural and promoter sequences of the MBL2 gene and is associated with variety of recurrent infections, including respiratory tract infections. We present a case of anhidrotic ectodermal dysplasia associated with severe mannose-binding lectin deficiency, never described in patients with anhidrotic ectodermal dysplasia.