Partial molar volumes at infinite dilution provide a convenient test of theoretical models of aqueous solutions. In this communication, previously published experimental results of the apparent molar volumes for NaCl, NaBr, LiCl, and CsBr at near-critical conditions were extrapolated to infinite dilution. In the temperature range included in this study (550 to 725) K, ionic association processes must be considered. Using recently proposed equilibrium constants for alkali halides included in this study, the extrapolations were corrected for ion-association effects. Partial molar volumes at infinite dilution for free ions and ion pairs are reported for each electrolyte.