Abstract: An aerodynamic cycling helmet is described, comprising a shell developed along a longitudinal direction, from a front area to a rear area, the said rear area extending beyond an inner portion of the shell provided with an occipital support of the head, the said shell being symmetrical with respect to a longitudinal plane of symmetry containing the longitudinal direction and extended in two opposing side walls from a temporal area and the area of the ear to the rear area. On each of the side walls, the helmet is provided with a respective air intake, which is open and passing through the shell and the shell includes in the rear area, within the shell, respective surfaces for channelling the flow of air that are capable of straightening, parallel to the longitudinal direction, the air flow derived from each of the air intakes and of channelling the flow, within the shell, in the direction of the rear area of the shell.