Sloan and Fleyfel (Sloan, E.D. and Fleyfel, F., 1992. Hydrate dissociation enthalpy and guest size. Fluid Phase Equilibria, 76 : 123-140) claim that the dissociation enthalpies of hydrates are determined by the size of the guest molecules, and that they are independent of the type and concentration of the guest gas. This conclusion does not seem to be obvious when the effect of the different amounts of water per mole of gas are eliminated from the data.