The paper studies the relationships between degree of graphitization (P 1 ) and galvanomagnetic properties [maximum magnetoresistance (Δδ/δ) maximum Hall coefficient RH and electrical resistivity Q] for pyrolytic carbons and cokes treated at different temperatures. With increasing heat treatment temperature, sign changes from negative to positive in (AQ/Q) m a x and from positive to negative in RH took place at P 1 0.5, irrespective of the specimen. Such a phenomenon implies that electronic conduction in these specimens changes from a one-carrier type to a two-carrier type when the three-dimensional graphitic stacking order becomes predominant in the volume fraction. Galvanomagnetic parameters as a function of P 1 depend considerably on the texture of the C materials. However, a positive value of (AQ/Q) m a x was observed as a unique function of the crystallite size of the hexagonal C layers, independent of the specimen. The degree of orientation of the hexagonal layers strongly affects the absolute value of RH.