The effect of excluded volume interactions on the static light scattering of mixed cylindrical micelles of hexadecyltrimethylammonium bromide (C(16)TAB) and hexaethylene glycol monododecyl ether (C(12)E(6)) in aqueous 0.5 M KBr solutions is discussed. Both the osmotic compressibility and the correlation length of these wormlike micelles can be described reasonably well in terms of a model for self-assembled hard rods.