The Department of Energy (DOE) facilities are responsible for producing, storing, and handling significant quantities of nuclear materials, weapons, classified information, and equipment, creating a need for extensive initial and ongoing training in the interest of national security. Emergency Operations (EO) staff throughout the entire DOE complex must have the knowledge, skills, and abilities (KSA) to respond to any site/facility/transportation emergency and to any radiological or nuclear crisis or emergency. Therefore, it is essential that EO staff training be designed complex-wide not only to maintain but to improve human performance in responding to a radiological or nuclear emergency. As one of the initial activities in designing a comprehensive staff training program, a first-ever, complex-wide, functional analysis was performed. Spanning several months and involving the Nonproliferation and National Security Institute (NNSI), the Emergency Operations Training Academy (EOTA), DOE, and TRW, this pioneering effort took an in-depth, national approach to data collection, resulting in comprehensive analysis of 15 EO staff performance functions, which were comprised of 613 performance tasks, and subtasks. Quantitative survey results relied on response ratings using 5-point Likert scale and applied within a Training Recommendations Decision Tree. Overall, the data reflected an overwhelmingly large number of recurring training task recommendations within all EO functional areas. Of the 613 total tasks addressed, only two (<1%) were recommended for informal (on-the-job) training. In addition to quantitative data, the survey asked respondents to provide comments regarding training needs for each functional area. Also, table-top interviews with EO staff regarding the functions were performed at various nuclear sites around the country. This allowed an opportunity for further participant input and perspective on the EO performance and training issues. The application of this phased, quantitative/qualitative, systems-based approach provided significant insight into EO training program needs for the future. This comprehensive, complex-wide training analysis supported the development of standard training requirements for effective EO course design and development at DOE sites across the U.S.