Recently, acute interstitial nephritis (AIN) presenting nephrotic syndrome and renal failure induced by nonsteroidal anti-inflammatory drug (NSAID) has been recognized with increasing frequency. We described here a 43-year-old woman who developed this type of nephropathy after taking NSAID for rheumatoid arthritis. Flurbiprofen (Froben) was assumed to be a causal drug based on a clinical course and a positive result of lymphocyte transformation test. Withdrawal of flurbiprofen therapy led no sufficient improvement, and high-dose steroid therapy done 15 months after the onset resulted in only a minor improvement. So far as we know, this was the second case of AIN associated with flurbiprofen and the youngest in NSAID-induced AIN with irreversible chronic renal insufficiency.