A mixer, for use with an internal combustion engine, for mixing EGR gas from an EGR loop with fresh air from the engine's fresh air intake. The mixer has an outer shell having the general shape of a thin-shelled hollow cylinder with a side entry port. One end of the cylinder provides a straight entry port and the other end of the cylinder provides a straight exit port. An inner sleeve fits inside the outer shell such that a space is provided between the inner sleeve and the outer shell, and a passageway is formed inside the inner sleeve through the length of the mixer. The inner sleeve has a series of flow ribs extending from its outer surface within the space, and has entry holes for providing fluid communication from the space into the passageway.