Makowski et al. [9] determined the potential of mean force for the association of two fullerene molecules in TIP3P water, at room temperature, and found that the water contribution contrasts pairwise hydrophobic interaction. In the present Letter this result is rationalized by showing that the decrease in water accessible surface area upon association causes both a gain in configurational/translational entropy of water molecules and a loss of a significant fraction of fullerene-water attractive energetic interactions. The latter term proves to be larger in magnitude than the former because the carbon atom density on fullerene molecular surface is markedly greater than that of normal hydrocarbons. (c) 2010 Elsevier B. V. All rights reserved.