In this article, a comparison of the performance of COSMO-SAC and COSMO-RS(OI), using a profiles generated by different quantum mechanic programs (Gaussian 03, Turbomole and DMol3) and different model Chemistries, with respect to activity coefficients at infinite dilution and vapor-liquid equilibrium data of binary systems, is presented. Density functional theory (BP and B3LYP) was used for the COSMO calculations. The basis sets used for the calculation were triple-zeta valence polarization (TZVP) and 6-311G(d,p). DMol3 results were taken from the publicly available VT 2005 databank. The predicted results were compared with the experimental data stored in the Dortmund Data Bank. The results showed that the a profiles from B3LYP with 6-311G(d,p) basis set generated by Gaussian 03 lead to the best results for most binary systems; COSMORS(01) is superior to COSMO-SAC for predicting the thermodynamic properties of binary systems in most cases. Calculation results were analyzed, with respect to the types of components in the mixture. It can be expected that the performance of the models, when combined with B3LYP/6-311G(d,p), can be improved by adjusting the model parameters.