Wet impregnation with phenolic resin and P-CVI methods were used to manufacture C/C composites. The influence of impregnation process of porous 2D carbon fibre substrate with resin and pyrocarbon deposited by CVD technique on mechanical properties of formed composites was studied. The results indicate that using P-CVI method large pores remain in the matrix resulting in lower mechanical strength. This fraction does not undergo any changes during thermal treatment. The flexural modulus of C/C composites depends mainly on the type of reinforcing fibres. The values of moduli measured in composites obtained by both methods do not differ significantly. Comparison of two methods of fabrication of C/C composite show that much better strengths can be achieved by forming the carbon matrix in solid state.