Synovial cysts are not uncommon in rheumatoid arthritis. These periarticular herniations of the synovialis are not difficult to diagnose in peripheral joints but have rarely been identified in the hips. A patient who presented with femoroinguinal swelling is presented. This swelling proved to be a synovial cyst originating from the hip joint. The diagnosis of synovial cyst should be considered whenever femoroinguinal swelling occurs in a patient with rheumatoid arthritis.