The linear dimensional changes of anisotropic and near-isotropic graphites were measured after irradiation in the range 300 to 1500ยฐC to 3.3 x 102r n/cm" (E > 0.18 MeV). The presence of a nongraphitizing impregnant coke in an anisotropic needle-coke graphite increased its volume contraction, reduced the anisotropy of dimensional contraction, and retarded turnaround in the direction perpendicular to extrusion. No changes in the thermal expansivities were observed but all graphites studied exhibited a single linear relationship between thermal expansivity and linear dimensional change at 320 to 615ยฐC. A separate linear relationship was observed for anisotropic or near-isotropic graphites at 840 to 1500ยฐC. There was a shift toward higher contraction for the near-isotropic graphites. Thermal conductivities, measured at room temperature, were lower than thepreirradiation conductivities. Fractional reductions ranged from 85 per cent after irradiation at 300ยฐC to 35 per cent after irradiation at 1250 to 1500ยฐC. After irradiation at 1200ยฐC conductivity changes were annealed out of anisotropic graphites at 15OO"C, while 2600ยฐC was necessary to remove the changes from a near-isotropic graphite.