The crystal structure of the diacetate of (+)-epipinoresinol, C24H26O8, has been determined by single-crystal diffraction methods. The compound crystallizes in the monoclinic space groupP21 witha=7.506(3),b=8.526(4),c=17.746(8) A,β=97.12(4)° andZ=2. A total of 3504 reflexion intensities were recorded on a Syntex P21 diffractometer (MoKα radiation) at room temperature. The structure was solved by direct methods and electron density calculations. Full-matrix least-squares refinement gaveR=0.056 for 2297 observed [I>3σ(I] reflexions. The individual central tetrahydrofuran rings have envelope conformations with coplanar carbon atoms and the oxygen atoms as flaps; the carbon atom planes form an angle of 119.9(3)°. Bond distances are C-C (aromatic) 1.386(12) A, C(sp 3)-O 1.421(12) A, C(sp 2)-O 1.372(20) A, and C(sp 2)=O 1.186(9) A. The influence of molecular structure on the positions of signals in the1H nmr spectrum of the diacetate of (+)-epipinoresinol is discussed.