The partition coefficients for a large number of macrocyclic crown ethers in different water-organic biphasic systems at BP-SVP-AM1 and BP-TZVP level of theory using novel conductor like screening model for real solvents (COSMO-RS) approach are presented here for the first time. The predicted values of partition coefficient obtained from the present calculation are compared with the available reported experimental results. The calculated values of partition coefficient obtained from the first principle based COSMO-RS theory are in reasonably good agreement with the available experimental results. The present study reveals that the solvents with strong hydrogen bond donating, weak hydrogen bond accepting and high dipolarity/polarizability are the good solvents for partitioning of a neutral organic solute. The partitioning of a neutral solute in a particular solvent is enhanced due to increased hydrophobicity. (C) 2009 Elsevier B.V. All rights reserved.