The present investigation was concerned with the improvement of flexural properties of carbon fibre-reinforced polymer (CFRP) composites through partial substitution of E-glass fibre (SE 2350 Type 30) for carbon fibre (Pyrofil TR50S 12K) in an epoxy (Kinetix R240) matrix. The flexural properties of the composites were determined according to the ASTM D790-07 standard with the span-to-depth ratios of 16, 32 and 64 being utilised whilst fibre volume fraction were determine from image analysis of optical micrographs. The flexural strength was noted to increase with higher span-to-depth ratios due to the reduce influence of shear stresses when compared to axial stresses. A positive hybrid effect was noted for flexural strength, strain at maximum stress, and specific energy storage at maximum stress. In contrast to these, the elastic modulus appears to obey the rule of mixture equation with a decreasing trend following the substitution of the lower modulus glass fibre.