A linear relation has been found between the ESR g-value anisotropy, the electrical resistivity ρ300K, the resistivity ratio ρ77K/ρ300K, the thermoelectric power and the magnetoresistance of a large number of carbon fibres based on polyacrylonitrile precursors and processed in a variety of ways (including hot stretching techniques) above 1750 °C. These correlations also appear to extend to cellulose-based fibres. Accordingly a term `relative graphitic order' is introduced in this paper, and is defined empirically as the resistivity ratio in order to represent the structural order of the graphite more effectively than the heat treatment temperature which has been used by previous workers. The relative graphitic order also shows a linear variation with x-ray crystallite size. The data suggest that those fibres with the highest relative graphitic order resemble the stage attained by soft (graphitizing) carbons after heat treatment close to 2200 °C; that is, the stage immediately preceding the appearance of 3-dimensional order and the onset of rapid graphitization It has also been found that the magnetoresistance is related to the alignment of these fibres, and can be used to deduce the preferred orientation.