Abstract: A sensitive and rapid high- performance liquiu chromatographic method has beendeveloped for the determination of dicfofenac in human serum.The average recovery of diclofenacwas 98.2%to 102.5%.The relative standard deviation was 1.29%to 4.52%.The calibrationcurve was linear in the range from 0.2μg/ml to 10.0μg/ml with r= 0.9999.The detection limit ofthe method was 1 0 ng/ml.The serum drug concentration—time curve exhibited a 1-compartmentopen model and the mean T_1/2 was 2.15 h.