The total extract of resin from Callitris preissii was analyzed by gas chromatography/mass spectrometry and 34 lignans, underivatized and as trimethylsilyl ether derivatives, were identified by interpretation of the mass spectra. The lignans in the resin include 13 new lignans, i.e., four secoisolariciresinol derivatives, four lariciresinol derivatives, 3′,4′-methylenedioxy-7′-hydroxylariciresinol, 3,4-methylenedioxypinoresinol isomer, and two matairesinol derivatives. Furthermore, 17 lignans of the resin are characterized by methylenedioxy substitution on either or both guaiacylpropyl units or the syringylpropyl unit: i.e., five secoisolariciresinol derivatives, three lariciresinol derivatives, 3′,4′-methylenedioxy-7′-hydroxylariciresinol, three pinoresinol derivatives, and five matairesinol derivatives, have methylenedioxy structures. Eleven lignans, including two secoisolariciresinol derivatives, four lariciresinol derivatives, two pinoresinol derivatives, and three matairesinol derivatives, contain a syringyl moiety.