The graphite and carbon materials used for the core support graphite components of High Temperature Engineering Test Reactor (HTTR) are nuclear grade fine-grained isotropic graphite (IG-110), nuclear grade medium-grained near-isotropic graphite (PGX) and coarse-grained carbon (ASR-ORB). The material data on properties such as tensile strength, compressive strength, Young`s modulus, thermal expansion etc. of these graphites and carbon have been acquired up to now. From these obtained data the design data were stipulated by the graphite structural design code of core support graphite components of HTTR in order to design the core support graphite structures. This report explicates these design data for the core support graphite and carbon components of the HTTR. (author).