This chapter considers the application of radiation for sterilization of a product, the effect of the radiation on the materials that make up the products and packaging. The breakdown products found after irradiation are identical to those found during manufacture of a drug, or are metabolites of the drug. The majority of polymers used are radiation stable at doses typically used to sterilize health care products. However, all polymer selections should be thoroughly challenged in the specific application and processing conditions. Products should be exposed to doses higher than expected for routine sterilization, and non irradiated controls should be included in the program. Bioburden histories for individual products should be maintained over time. Bioburden data should be collected on an established time frame for all products within the family to ensure that the selected representative product continues to be the most difficult to sterilize item in the group.