Acacia and Eucalyptus wood chars, prepared at various temperatures in the range 400-1200-degrees-C, have been studied by X-ray diffractometry. The objective was to investigate the changes in structural ordering in relation to carbonization temperature and time. For both the Acacia and Eucalyptus wood chars, the apparent interlayer spacing (d002) decreased slightly while the apparent microcrystallite diameter, L(a), increased markedly with increasing carbonization temperature. The trend was, in general, similar with increased soaking time at carbonization temperatures of 800 and 1000-degrees-C, but these X-ray properties (i.e. d002 and L(a)) were found to be more susceptible to carbonization temperature than to time. The results also showed that both the wood species, when carbonized under identical conditions, yielded chars with practically similar diffraction profiles.