Densities of solutions of H2O and D2O in nitromethane, with the solute mole fractions ranging up to 0.03, were measured with an error of 1.5 . 10(-5) cm(3) . mol(-1) at (278.15, 288.15, 298.15, 308.15, and 318.15) K using a vibrating-tube densimeter. Apparent and partial volumes and isobaric expansibilities (down to the infinite dilution) of water isotopologues were calculated. The temperature-dependent behavior of D2O-H2O solute isotope effects on the molar quantities studied were described taking into account the structure- and interaction-related peculiarities of the dissolving medium in question. (C) 2010 Elsevier Ltd. All rights reserved.