The Mongolian pine borer, Dioryctria mongolicella Wang & Sung (Lepidoptera: Pyralidae), is a major pest in Mongolian pine (Pinus sylvetris L. var. mongolica Litvinov) plantations in the northeast of China. A blend of 11-hexadecenal and 11-hexadecenyl acetate in a ratio of 2:1 was detected from extracts of its female sex pheromone glands by gas chromatography–mass spectrometry. Our field trapping experiments confirmed that the D. mongolicella pheromone consists of a blend of (E)-11-hexadecenal (E11-16:Ald) and (Z)-11hexadecenyl acetate (Z11-16:Ac). The addition of (Z,E)-9,11-tetradecadienyl acetate (Z9E11-14:Ac) and (Z,Z,Z)-3,6,9-tricosatriene (ZZZ3,6,9-23:H) increased catches of male D. mongolicella in sticky traps baited with E11-16:Ald and Z11-16:Ac. However, the addition of (3Z,6Z,9Z,12Z,15Z)-pentacosapentaene or (Z,Z,Z,Z,Z)-3,6,9,12,15-tricosapentaene to lures loaded with E11-16:Ald, Z11-16:Ac, and Z9E11-14:Ac did not significantly increase trap catches of D. mongolicella at two locations in Heilongjiang province, China. The synthetic blend of 400 µg E11-16:Ald, 200 µg Z11-16:Ac, 200 µg Z9E11-14:Ac, and 500 µg ZZZ3,6,9-23:H will help in developing efficient strategies for monitoring and control of D. mongolicella populations in Mongolian pine plantations.