Mutual diffusion coefficients (interdiffusion coefficients) have been determined for aluminium chloride in water at 298.15, 303.15 and 310.15 K at concentrations from 0.002 to 0.010 mol dm(-3) together with molar conductivity values. The diffusion coefficients were obtained by using a conductimetric open-ended capillary cell. The experimental data were discussed on the basis of the Onsager-Fuoss model. The Nernst diffusion coefficients derived from diffusion 1.208 x 10(-9) and 1.701 X 10(-9) m(2) s(-1) and from conductance 1.238 x 10(-9) and 1.692 x 10(-9) m(2) s(-1), at two temperatures 298.15 and 310.15 K, respectively, agree well each other. (c) 2007 Elsevier Ltd. All rights reserved.