Diffusion coefficients of monoalkyl ethers of poly(ethylene glycols), С₈Е₄ and С₁₂Е₅, and octyl-β-D-glucopyranoside have been measured in aqueous micellar solutions within wide ranges of temperatures and concentrations by dynamic light scattering. The study of the С₁₂Е₅–water system containing cylindrical micelles has been supplemented with viscosity measurements, which make it possible to better monitor structural transformations and phase transformations.