Lightscattering intensities have been measured on aqueous solutions of hexakis(ethylene glycol) n-dodecyl ether (C(12)E(6)), a typical nonionic surfactant, in the concentration range 10(-5)-10(-2) g cm(-3) which is 2 orders of magnitude lower:than those of literature data. The weight-averaged aggregation number of micelles, N-W, near the cmc is small (similar to 110) and depends on temperature only slightly in the range 15-45 degrees C. As the concentration increases, N-W slightly increases below a certain concentration (c(SP)) which decreases with increasing temperature. Above c(SP), N-W rapidly increases with concentration and then follows the power law N-W proportional to c(1/2).