Excess enthalpies and excess heat capacities at 25-degrees-C for the ternary system ethanol + tetrahydrofuran + cyclohexane, and for the related binary mixtures, were determined by means of a flow calorimetric apparatus built in our laboratory. Experimental data were described with a Redlich - Kister-type equation. Both H(E) and C(p)E ternary data show large positive contributions. Theoretical models were used for the description or prediction of experimental results. In the case of binary systems, the examined models are able to reproduce satisfactorily the experimental data for H(E), though less satisfactorily for C(p)E. Ternary experimental data are predicted by the modified UNIFAC method (Dortmund, Germany) but not by the Nitta-Chao model. Both these models are unsuccessful in predicting ternary C(p)E data.