A technique to determine the cross-linked fraction or gel content of polyethylene materials using a differential scanning calorimeter (DSC) is presented. The difference between the onset time of the melt peak of a neat sample and a cross-linked sample of the same material can be related to the gel content of the samples. To obtain a calibration curve, the gel content of samples determined using ASTM D 2765-01 (ref1) was related to the difference in onset time of the melting curve. The resulting calibration curve was used to predict the gel content of a different batch of polyethylene, and these results were compared to those obtained using D 2765-01. The two measured are found to be in excellent agreement. This technique is substantially faster, is less expensive, uses very little material, produces no hazardous waste, and is as accurate as the current ASTM standard.