In this study, a sensitive and accurate method for simultaneous separation and determination of three phenolic compounds (phenol, m-cresol and resorcinol) in water by revesed-phase high performance liquid chromatography using uv-visible detection has been described. Pre-column derivatization with 4-aminoantipyrine is used for the seperation and determination phenol, m-cresol and resorcinol in water. The derivatives formed within 5 min were extracted with chloroform and then analyzed by liquid chromatography with UV-visible detection at 440 nm. Chromatographic separation was performed using a reversed-phase column and acetonitrile-water (45:55%, v/v) as the mobile phase. The three derivatives were elueted in 13 min. The detection limits of phenol, m-cresol and resorcinol in a standard water sample were between 0.07 and 0.09 μg.L-1 for 100 mL respectively. The recoveries of the derivatives from pure water were betweeen 97.1-102.3% within relative standard deviations of 2.3-4.7%. The method was applied to the analysis of phenols in different water samples.