•Binary diffusion coefficients for the systems containing sodium hyaluronate.•Influence of the aggregation on diffusion of the sodium hyaluronate in the aqueous media.•Estimation of the thermodynamic and mobility factors from mutual diffusion. The Taylor dispersion technique has been used for measuring mutual diffusion coefficients of sodium hyaluronate in aqueous solutions at T=298.15K, and concentrations ranging from (0.00 to 0.50)g·dm−3. The results are interpreted on the basis of Nernst, and Onsager and Fuoss theoretical equations. From the diffusion coefficient at infinitesimal concentration, the limiting ionic conductivity and the tracer diffusion coefficient of hyaluronate ion were estimated. These studies have been complemented by molecular mechanics calculations.