Solvent effects on protonation equilibria of various aliphatic, alicyclic, and aromatic amines were estimated by means of a self-consistent isodensity-polarized electrostatic continuum model in combination with the B3LYP/6-31G* and B3LYP/aug-cc-pVDZ//B3LYP/6-31G* calculation schemes. Our results suggest that the found relationship between calculated relative and experimental basicities in water can be used for interpolation or extrapolation in order to calculate pK(a) values of organic bases with variable structural properties. The found standard deviation of calculated pK(a) values amounts to 0.7 pK(a) units. In this paper, we note successful use of this strategy as well as its limits.