We show that the behavior of entropy along the phase co-existence curves for rare gases can be analyzed based on the corresponding-states concept. To implement this concept, we consider dimensionless entropy Smu/R (R is the universal gas constant, mu is the atomic weight) +3 In B, where B is the de Boer parameter. It is demonstrated that such reduced entropy expressed in terms of reduced temperature T/D (D is the characteristic depth of the potential wells) is a universal function for all rare gases. (C) 2003 Elsevier B.V. All rights reserved.