The International Atomic Energy Agency reports numerous incidents of illicit trafficking in radioactive materials, including ionizing radiation sources (IRSs) used in medical, agricultural, and industrial applications. This report assesses the threats posed by inadequately protected IRSs in Russia and recommends steps to enhance the effectiveness of DOE’s current cooperative program with Russia. These continuing DOE’s current program of quick security fixes and developing a comprehensive plan to work with Russian counterparts to reduce overall risk, within the context of a comprehensive Russian program for ensuring adequate life-cycle management of IRSs.