Ai~traet--Experimental gel permeation chromatography calibrations have been obtained for polystyrene standards and linear polyethylene fractions in o-dichlorobenzene at 138 ยฐ. Intrinsic viscositymolecular weight data show that the two polymers in this solvent have similar polymer-solvent interactions. A predicted polyethylene molecular weight calibration is obtained from the experimental polystyrene standards calibration using equations which assume that hydrodynamic volume and the unperturbed mean-square end-to-end distance are universal calibration parameters. The difference between the two procedures is less than experimental errors. It is concluded that the procedures predict the same polyethylene calibration curve which passes through the experimental data for linear polyethylene fractions. Procedures for extrapolating the predicted polyethylene calibration to low and high molecular weights are described. The polyethylene calibration was used to calculate average molecular weights from an elution curve for a commercial polyethylene having a wide molecular weight distribution. The values are in reasonable agreement with those obtained by osmometry, viscometry and light scattering.