In considering a binary nucleation theory, it is shown that the unified approach to the homogeneous and heterogeneous nucleation theories makes it possible to obtain the equilibrium binary distribution satisfying both the mass action law and type II limiting consistency. Theoretical rates of binary nucleation are calculated by using the new equilibrium distribution, the distribution of Reiss, and that of Wilemski and Wyslouzil for the ethanol-hexanol system. Possible causes of the irregularity of discrepancies between theoretical predictions and experimental data are discussed.