Abstract: Anordrin (2a, 17a-diethyl-A-nor-5a-androstane 2β, 17β-diol dipropionate) is one of the widely used effective oral steroidal contraceptives. It consists of two epimers with greatly different biological activity. Variation of quantity ratio between these two epimers often causes uncertainty of action. Therefore, it is necessary to develop a method for determining both epimers accurately.After careful study of the chromatographic behaviours and configurational relationship between these epimers in various chemically bonded and silica gel supports, a bonded normal phase HPLC determination method is proposed. Epimers can be separated with THF/n-hexane (3～3.5%) in cyano- or aminobonded silica gel column and detected by UV detector at 225 rim.This study also revealed a correlation of the composition of epimer mixture with its melting heat (by DSC). The result shows that measurement of melting heat can be used as a simple but effective method for monitoring the drug quality.