Because of this disagreement we carried out the measurements of the size of ethanol aggregates by Zetasizer Nano ZS in the range of ethanol mole fraction in which their presence can be expected on the basis of the surface tension, density and viscosity measurements as well as the literature data. It appeared that the not ablevalues of the size of alcohol aggregates were obtained at first approximation in the range of its mole fraction corresponding to the break points on the surface tension, density and viscosity isotherms. From the dynamic lightscattering measurements it appeared that the aggregation of ethanol molecules takes place not only by the interaction of the hydrogen bonds but also of the hydrophobic ones because ethanol aggregates can include more than 5 molecules. It also turned out that the ethanol aggregation number increased slightly from 5 to 11 molecules (aggregate diameter range: 0.95–1.25 nm) in the range of its mole fraction in which the aggregation of its molecules was expected. The aggregation number of ethanol agrees with that found in the literature [26].