Background and objective: High-fidelity medical simulation is a source of stress for participants. The aim of this study was to assess if repeated simulated courses decrease perceived stress and/or physiological stress level and increase performance in anaesthesiology registrars. Method: Fourteen anaesthesiology specialty registrars participated individually in three successive sessions of crisis simulation in the operating room. Participants' perceived stress levels were measured by self-assessment (simple numerical scale from 0 to 10 [0 = no stress, 10 = maximum stress]) and physiological stress was estimated via the maximal heart rate measured by a Holter system). Technical and non-technical performances were also assessed. Data are expressed as medians with interquartile ranges and extremes (median (IQR [Min-Max])). Results: Between the first and third session, simulation repetition was associated with a decrease in perceived stress (9 (8-10 [5-10]) versus 7 (5-8 [2-9]) from session 1 to session 3 respectively, P = 0.02), whereas physiological stress assessed by the maximum heart rate remained unchanged (130 beats per minute (116-141 [85-170]) and 123 beats per minute (115-136 [88-166]) between sessions 1 and 3 respectively). There was also a significant inverse correlation between perceived stress levels experienced by registrars during the session and non-technical performance (P = 0.008). Conclusion: We observed a reduction in perceived stress levels experienced by registrars while physiological stress was unchanged with repeating simulation sessions combining simulated practice and debriefing. Learning through simulation could improve perceived stress management in critical situations. (C) 2016 Societe francaise d'anesthesie et de reanimation (Sfar). Published by Elsevier Masson SAS. All rights reserved.