Familial Mediterranean fever (FMF) is an inherited disorder characterized by lifelong recurrent, self-limiting attacks of fever and systemic inflammation. Rheumatoid arthritis is an erosive, chronic, inflammatory disease that affects mainly the wrists and joints of the hands. Development of rheumatoid arthritis in a patient with FMF is extremely rare. To our knowledge, this condition has been reported only once previously. Here, we present a 31-year-old female patient who developed rheumatoid arthritis during the course of FMF. In the patient, while the FMF was under control with regular use of colchicine, the rheumatoid arthritis was resistant to conventional therapies. Etanercept treatment provided complete remission in our patient.