This study examined the impact of Situation Presence Assessment Method (SPAM) administration on air traffic control (ATC) students’ task workload and performance in high-fidelity ATC simulations. ATC students performed high-fidelity en-route simulations in two conditions: baseline conditions (without SPAM questions) and SPAM conditions. The data collected show that while workload in the two conditions were not significantly different, there was a trend of higher mental workload in SPAM conditions than in baseline conditions. Performance immediately following SPAM questions was revealed to be poorer than that preceding the SPAM questions and that over the equivalent time periods in the baseline conditions. The results suggest that a "Ready" signal before a SPAM question may not be enough to eliminate the impact of SPAM administration on ATC students’ workload and performance in high-fidelity en-route simulations.