The crystal of dimethyl sulphoxide complex of yttrium [Y(NO33·3DMSO] belongs to the monoclinic system, α= 13.604(4)?, b= 12.669(4)?, c= 11.554(2)?, β= 100.14(4)° and Z=4. The space group is P21/n. The diffraction data were collected using PW-1100 four-circle diffractometer. The number of independent diffraction data amounts to 3615. The structure was solved by heavy-atom method. Structure parameters were refined by full matrix and block diagonal least square method to a final R = 0.080. The result of structure analysis establishes that the polyhedral coordination of " three-headger triprism" is formed by nine oxygen atoms surrounding the Y cation. The distances between the yttrium and the coordinating oxygens are Y-ODMSO = 2.285?, Y-ONO3-= 2.460?.