The sintering of compacted mesophase powders of varying nature and particle size was studied. The sintered carbons were stepwise heat-treated to 2600-degrees-C, and their properties were determined after each step. The sintering process is composed of a transient liquid-phase sintering step and a subsequent reaction sintering step in the solid state. The investigation of both process steps and the properties of the heat-treated carbons indicate that the initial transient liquid-phase sintering is the decisive step, and thus predetermines the properties of the heat-treated carbons. After graphitization treatment of sintered carbons at 2400-degrees-C, flexural strength values up to 160 MPa were obtained. Criteria for the selection of the mesophase, the particle size, and the sintering conditions are discussed.