The activity coefficients of methyl acetate (MeOAc), ethyl acetate (EtOAc), n-propyl acetate (n-PrOAc), n-butyl acetate (n-BuOAc), and n-pentyl acetate (n-PeOAc) have been measured at 25 °C in concentrated aqueous solutions of electrolytes using the distribution technique. The salts used were LiCl, NaCl, KC1, CsCl, KF, KBr, NaNOg, and NaC104. In general, the results obtained are as might be expected. A mechanistic explanation is given of the trends observed and unexpected features in the data are explained with the aid of some assumptions regarding the nature of ionic hydration. The apparent molar volumes of MeOAc have also been determined over the full range of molalities for each of the salts used in the activity coefficient determinations. These measurements are then used in conjunction with thermodynamic data for the salt solutions (from the literature) to calculate the MeOAc activity coefficients according to the expanded McDevit and Long equations developed in an earlier publication. Similar, but less accurate calculations have also been done for the activity coefficients of the larger esters. In these cases, apparent molar volumes were determined only in water. The calculations are found to have mixed success.