Nine different types of carbon fibres were used as the reinforcement component of the borosilicate glass DURAN. Optimum preparation procedures and parameters for the resulting composites were investigated, the mechanical properties were measured in the bending test, and the results compared. It was found that the densification of composites incorporated with high-modulus (hm) C-fibres could be done at lower temperatures than that of composites with high-strength (hs) C-fibres. The utilization of the fibres in the composites with respect to the tensile strength of the fibres was much better for the hm-C-fibres than for the hs-C-fibres. The experimentally obtained values for Young’s modulus and the bending strength of the composites were compared with those calculated from the linear mixing rule (LMR). The measured bendover stresses (stress limit of the elastic region in the stress-strain diagrams) were compared with those from the Aveston-Cooper-Kelly model, which calculates stresses at which cracks in the glass matrix occur. It has been shown that good agreement between experimental and calculated values was found if relatively large values were assumed for the interfacial shear strength.