This book constitutes the proceedings of the 17th International Conference on Engineering Psychology and Cognitive Ergonomics, EPCE 2020, held as part of the 22nd International Conference, HCI International 2020, which took place in Copenhagen, Denmark, in July 2020. The total of 1439 papers and 238 posters included in the 37 HCII 2020 proceedings volumes was carefully reviewed and selected from 6326 submissions. EPCE 2020 includes a total of 60 regular papers; they were organized in topical sections named: mental workload and performance; human physiology, human energy and cognition; cognition and design of complex and safety critical systems; human factors in human autonomy teaming and intelligent systems; cognitive psychology in aviation and automotive. As a result of the Danish Government's announcement, dated April 21, 2020, to ban all large events (above 500 participants) until September 1, 2020, the HCII 2020 conference was held virtually.