Glycerol kinase from the hyperthermophilic archaeon Thermococcus kodakaraensis was crystallized and preliminary crystallographic studies of the crystals were performed. Crystals were grown at 293 K by the sitting-drop vapour-diffusion method. Native X-ray diffraction data were collected to 2.4 angstrom resolution using synchrotron radiation at station BL44XU of SPring-8. The crystal belongs to the rhombohedral space group R3, with unit-cell parameters a = b = 217.48, c = 66.48 angstrom. Assuming the presence of two molecules in the asymmetric unit, the V-M value was 2.7 angstrom(3) Da(-1) and the solvent content was 54.1%. The protein was also cocrystallized with substrates and diffraction data were collected to 2.7 angstrom resolution.