Dependences of dielectric permittivity ɛ(f) and dielectric loss tangents tansδ(f) of aminoalcohols (AAs), polyethylenepolyamines (PEPAs), water, and aqueous solutions of AAs and PEPAs with water concentrations of 1 wt % are investigated in the frequency range of 0.025–1000 kHz. The dielectric relaxation of the liquids under study is investigated. An interrelation between the dielectric parameters and physicochemical properties of AAs and PEPAs is established. Empirical equations that describe this interrelation with a high degree of accuracy of approximation validity are derived. The effect of water on the dielectric characteristics of AAs and PEPAs is shown. It is suggested that we evaluate the energy of affinity of AAs and PEPAs for water using the coefficient of dielectric losses ɛ″.