Extracts of female sex pheromone gland of the carpenterworm moth, Holcocerus hippophaecolus Hua, a pest of sandthorn, Hippophae rhamnoides L. were found to contain (E)-3-tetradecenyl acetate (E3-14:Ac), (Z)-3-tetradecenyl acetate (Z3-14:Ac), (Z)-7-tetradecenyl acetate (Z7-14:Ac), the corresponding alcohols, E3-14:OH, Z3-14:OH, Z7-14:OH, and (E)-9-tetradecenyl acetate (E9-14:Ac). Electroantennographic (EAG) analysis of these chemicals and their analogs demonstrated that Z7-14:Ac elicited the largest male EAG response, followed by E3-14:Ac. In field trials, traps baited with either Z7-14:Ac or E3-14:Ac alone caught no male moths, whereas a combination of these two components in a 1:1 ratio caught more males than control traps. Addition of Z7-14:OH and Z3-14:OH or the alcohols plus E9-14:Ac did not enhance trap catches. We conclude that the sex pheromone of H. hippophaecolus is composed of Z7-14:Ac and E3-14:Ac. Optimal ratios and doses of these two components, and the possible role of other minor components, remain to be determined.