Mutual diffusion coefficients of alkane-1,n-bis(trimethylammonium bromide), CnMe6Br2 (n = 8, 10, 12), surfactants have been measured using the Taylor dispersion technique, at T = 298.15 K, at concentrations from (0.000 to 0.0380) mol . dm (3). The dependence of mutual diffusion coefficients on the concentration has been discussed in the framework of Onsager-Fuoss and Pikal models. On the basis of this discussion, it is suggested that these surfactants behave as associated electrolytes. From limiting mutual diffusion coefficient values, extrapolated from experimental values for c -> 0, limiting ionic conductance, tracer diffusion coefficients, and hydration radii of alkane-1,n-bistrymethyl ammonium ions have been estimated. For the case of dodecane-1,12-bis(trimethylammonium bromide), no aggregation has been noticed up to 0.04 mol . dm (3). (c) 2012 Elsevier Ltd. All rights reserved.