Polymer degradation has been studied by using gel-permeation chromatography (GPC) to measure the product distribution. The method is rapid and has a good accuracy that permits one to see most of the degradation products, as they elute at a point different from the starting material. In the cases studied, polystyrene cleavage has the result of random cleavage, as judged by the product distribution. A GPC curve to be expected from random cleavage has been put together to aid in the evaluation. Both wide and narrow molecular weight distribution polystyrenes have been studied after degradation. The narrow distribution products were degraded by peroxides, irradiation, and weathering. With the latter, the combination of simple fragments to form the starting portions of cromslinking were measured in small amounts. In none of the cases studied did degradation in solution produce crosslinked products. Kinetic rate studies were made that concerned the action of peroxides and inhibitors.