A simple, sensitive and validated HPLC method has been developed to determine gemfibrozil and simvastatin simultaneously in synthetic mixture form. Chromatographic separation was achieved on a C-18 column using a mixture of 0.1 M ammonium acétate pH 5.0 and acetonitrile in the ratio of 15:85 (v/v) at a wavelength of 237 nm. Linearity of the method was found to be in the concentration range of 60-420 µg/ml forugemfibrozil and 1-7 µg/ml for simvastatin with correlation coefficient greater than 0.9999. The total eluting time for the two components is less than ten minutes. The method can be used for simultaneous determination of gemfibrozil and simvastatin