A high performance liquid chromatographic method has been developed for the simultaneous analysis of non-steroidal anti-inflammatory drugs in plasma. The simultaneous determination of ibuprofen, fenoprofen and ketoprofen is performed by RP-HPLC with UV detection. The chromatographic system consisted of Spherisorb octyl column$(5{mu}m)$ ; the mobile phase was $acetonitrile;-;0.5\%$ phosphoric acid(55 : 45, v/v) and the detection wavelength was 230nm. Tolmetin was employed as an internal standard. The method described is rapid and simple with sensitivity limits of $2.0{mu}g/ml$ ibuprofen, $0.5{mu}g/ml$ fenoprofen and $0.3{mu}g/ml$ ketoprofen and is suitable for routine clinical and pharmacokinetic studies.