Abstract The present work is concerned with determining a good effective isotropic pair potential energy for carbon dioxide by the use of two-iteration inversion of corresponding states correlation of viscosity. The Lennard-Jones (12-6) model potential has been employed, as the initial model required by the inversion method. Calculation of transport properties using the inverted potential is discussed. A rather accurate correlation for viscosity is reproduced from the inverted intermolecular potential energy. The accuracies are to within 1% in the temperature range 200< T<350 and 0.4% in the temperature range 350< T<1500 K for the viscosity. Also inverted potential energy is used to calculate thermal conductivity coefficients with accuracy 3% over the temperature range 250< T<2000 K. The calculated potential energy function has been compared with a spherical two-center exp-6 potential function proposed by others.