Vapour liquid equilibria data of the electrolyte system water-lithium bromide can be correlated accurately by using a so-called solvation model. This model assumes the formation of ion clusters, i.e. Li+ or Br- ions surrounded by water molecules, the number of which depends on the overall molar concentration of lithium bromide. The activities of the various components in the liquid phase are modelled by Wilson’s equation. The vapor phase, assumed to consist of water only, is modelled by the EOS of Wagner and Saul. The model includes seven parameters fitted to 388 experimental data points taken from the literature in the range 0.00015-0.316 MPa, 273-463 K, 5-76 wt% LiBr. The pressure of the system resulting from a T, x --> p calculation procedure can be represented with a mean relative deviation of less than 1.6%.