Carbon disulfide, CS2, mp = 161.7 K, has been crystallized in situ in a diamond-anvil cell at 295 K and 1.26 GPa to give an orthorhombic Cmca structure. No phase transitions occur with further increasing pressure till the polymerization onset at 8 GPa. The crystal structure was determined by direct methods from single-crystal X-ray diffraction at 295 K at two pressure points: 1.8 and 3.7 GPa (esd's in the lengths of C=S bond 0.0001 nm). The molecular rearrangements have been rationalized by the close packing and equidistant (SS)-S-... intermolecular interactions enforced by pressure. Although only slight lengthening of the covalent double C=S bond has been observed till 3.7 GPa, the intensified intermolecular (SS)-S-... and (CS)-S-... interactions reveal the possible reaction pathways of pressure-induced polymerization of CS2.