Adult onset Still's Disease (ASD) is a systemic inflammatory disorder of unknown etiology characterized by chronic and fluctuant fever with accompanying rash, polyarthritis and involvement of multiple organs, especially lymphoid tissues. Although kidney involvement may appear in some cases of adult Still's disease, membranous glomerulonephyritis has not been described before. We herein report a 38-year-old man diagnosed with Still's disease with longstanding polyarthritis unresponsive to high-dose steroids and various immunosuppressive drugs for 5 years. He was referred to our clinic with bilateral pretibial edema on his legs. Urine examination revealed 10.5 g/day proteinuria with membranous glomerulonephritis and his renal biopsy came up with it. Infliximab was initiated, and his complaints were totally resolved also with a normal urine test in the following 3 months. To the best of our knowledge, this is the first report that clearly shows the efficacy of infliximab in a patient with refractory ASD with membranous glomerulonephyritis.