Six crystals forms of the same self-complementary deoxyhexamer pCpGpCpGpCpG have been obtained by the crystallization method developed previously [Malinina et al., J. Biomol. Struct. Dynam. 5 (1987) 405]. The crystals belong to different space groups and have different structural parameters. The "fiber-like X-ray patterns" calculated on the basis of single crystal X-ray data confirms that in these crystals the double helix of the hexamer adopts various conformations including one similar to B-DNA.