The invention relates to a wind turbine blade having at least one component formed of a fibrous composite material including two or more different types of carbon fibres having a different elastic modulus to each other. The proportions of the different types of fibres vary in the longitudinal direction of the blade such that the elastic modulus of the fibrous composite material increases towards the tip end of the blade. The two or more different types of carbon fibres may be incorporated in an inner beam and/or in the outer shell portions of the blade.