Solution densities at T = 298.15 K have been determined for adenosine in the mixed solvents (H2O + y), y = thymidine, uridine, and cytidine at the nominal molalities (0.051, 0.075, and 0.100) mol . kg(-1), and for 2'-deoxyguanosine in the mixed solvents (H2O + y), y = thymidine and cytidine at the same nominal molalities. The partial molar volumes at infinite dilution, V-2(degrees), for adenosine and 2'-deoxyguanosine in the mixed solvents obtained from the density data were used to evaluate the volumes of transfer for the solutes at infinite dilution from water to the mixed solvents, Delta V-tr(2)degrees {H2O -> (H2O + y)}. Using the McMillan-Mayer approach for the treatment of transfer thermodynamic functions, volumetric interaction coefficients that represent the pairwise interactions between solvated nucleosides were evaluated. These pairwise interaction coefficients were interpreted in terms of the likely interactions between the hydrated nucleosides. (c) 2013 Elsevier Ltd. All rights reserved.