Values of the enthalpy of dilution were measured for L-prolinol in pure water and N,N-dimethylformamide (DMF) aqueous solutions with various mass fractions of DMF at T = 298.15 K using a flow-mixing microcalorimeter. A pseudo phase equilibrium model was proposed to simplify the complex aggregation equilibrium and interpret the abnormality in the dilution enthalpy, which together with the McMillan-Mayer approach was used to fit the experimental data to obtain the enthalpic pairwise interaction coefficients and the molar aggregation enthalpies of L-prolinol in DMF aqueous solutions. The results are discussed in terms of the hydrophobic interaction and the interactions between the solvated solutes. (C) 2012 Elsevier Ltd. All rights reserved.