Excess molar volumes, V-m(E), at 298.15 K and, atmospheric pressure over the entire composition range for binary mixtures of 2-butanone with di-n-butyl ether and 2-pentanone and 3-pentanone with di-n-butyl ether and 2,5-dioxahexane, 2-heptanone and 4-heptanone with di-n-butyl ether, 2,5-dioxahexane and 3,6,9-trioxaundecane are reported from densities measured with a vibrating-tube densimeter. All the excess volumes present strong contractions when compared to those of n-alkanone + n-alkane systems. Molar excess enthalpies H-m(E) and V-m(E) of the considered mixtures vary similarly. This may be attributed to interactional effects which prevail over structural effects. Flory's theory has been applied to the systems under study. As expected, results for H-m(E) are better when the difference in polarity of the components of the mixture decreases. V-m(E) is often poorly represented.