CDC continually evaluates its Emergency Management Program (EMP) activities, including Incident Management System (IMS) activations, use of EMP functions (referred to as EMP utilizations), and exercises, to ensure that the agency is ready to respond to infectious disease outbreaks, disasters (human-made or natural), and security events. Such evaluation not only documents baseline preparedness and response activities during a selected analytical period, but also highlights significant EMP actions that can guide and inform future emergency operations. To characterize EMP activities that occurred during January 1, 2013-December 31, 2018, CDC conducted a retrospective analysis of operational activity logs. The results showed 253 domestic (U.S. states and territories) and international EMP activities, including 12 IMS activations, 147 EMP utilizations, and 94 exercises. Infectious diseases were the most common threat among both IMS activations (58%) and EMP utilizations (52%). CDC responded to the 2014 Ebola epidemic and the 2016 Zika outbreak; each response lasted approximately 2 years and required extended collaboration with domestic and international partners. Understanding the trends in EMP activities, including knowing the most common threats, aids CDC in allocating resources and focusing preparedness efforts. In 2013, CDC became the first federal agency to receive full agency-wide accreditation by the Emergency Management Accreditation Program (EMAP) in recognition of CDC's commitment to preparedness and its ability to respond to domestic and global public health threats. CDC received EMAP reaccreditation in December 2018 (1,2).