Betulin is a lupane triterpenoid [lup-20(29)-ene3b,28-diol, C 30 H 50 O 2 ] showing high biological activity. This activity is supposed to be strongly affected by the molecular structure of its polymorphic forms. Different solvate polymorphic forms of betulin have aroused increasing interest as the possible anticancer agents of natural origin. X-ray diffraction was used to investigate crystal structure of (1:1) betulin-DMSO solvate. Title compound crystallizes in the orthorhombic P2 1 2 1 2 1 space group. Unit cell parameters are as follows: a = 7.0006(2) Å , b = 12.1623(3) Å , c = 33.6991(8) Å , Z = 4. Crystal packing and selected geometric parameters are described. It has been found that the hydrogen bonding and the dipole-dipole interaction between DMSO molecules play the major role in the formation of the crystal structure.