Ternary mutual diffusion coefficients measured by the Taylor dispersion method (D-11, D-22, D-12 and D-21) are reported for two aqueous systems, that is, potassium chloride and 2-hydroxypropyl-beta-cyclodextrin (HP-beta CD), and potassium chloride and beta-cyclodextrin (beta CD) at T = 298.15 K and T = 310.15 K, and at carrier concentrations from (0.000 to 0.010) mol.dm(-3) for each solute. Based on these data, some conclusions about the influence of KCl on the diffusion of the cyclodextrins (HP-beta CD and beta CD) were made, and the association constants of the complexes formed between the two components for each system (KCl and beta CD, and KCl and HP-beta CD) were estimated. (C) 2012 Elsevier Ltd. All rights reserved.