In this work, the solubility of carbon dioxide, CO2, in pentaerythritol tetrapentanoate (PEC5) and in pentaerythritol tetra(2-ethylhexanoate) (PEBE8) has been performed from (283 to 333) K and pressures up to 7 MPa in a new high-pressure gas solubility apparatus. The results show that in the present analyzed range CO2 is highly soluble in these oils and that the solubility expressed as CO2 mole fraction is practically not dependent on the branching of the acid chain, whereas it increases slightly with the length of the PE acid chains in the present range of compositions. The gas solubility data were satisfactorily correlated with the Soave-Redlich-Kwong (SRK) equation of state (EOS) using the conventional quadratic mixing rule with two interaction parameters for each temperature.