Guggulipid, the standardized product from the extraction of the ole-gum-resin from the Commiphora mukul plant, has been marketed as a hypolipidemic agent. The ketosteroids, cis- and trans-4,17(20)-pregnadiene-3,16-dione, known as E- and Z-guggulsterones, respectively, are the main ingredients in guggulipid. A liquid chromatographic method was developed for simultaneous determination of E- and Z-guggulsterones in guggulipid preparations using synthetic E- and Z-guggulsterone standards. Realtively low amounts of guggulsterones (E and Z) were found in commercial guggulipid preparations in comparison with the manufacturer's claim of 2.5%. The mixture of E- and Z-guggulsterones was extracted and separated on a Symmetry C18 reversed-phase column, with a mobile phase of acetonitrile--water (46 + 54, v/v) and detected at 242 nm. The retention times of E- and Z-guggulsterones are approximately 8 and 11 min, respectively. Assay quantitation was based on the calibration curve obtained from a mixture of synthetic standard E- and Z-guggulsterones. Experimental data on selectivity, linearity, accuracy, and recoveries are presented.