BACKGROUND: In the Difficult Airway Society's 2015 "cannot intubate, cannot oxygenate" guideline, the emergency cricothyroidotomy is the final option when managing an unanticipated difficult airway. How often training for maintenance of this skill is required for anesthesiologists remains unknown. We aimed to assess if specialist-trained anesthesiologists' skills improved from a brush-up intervention and if skills were retained after 3 months. METHODS: In this multicenter, randomized, controlled trial, participants were randomized to either a simulation-based brush-up or no brush-up. Both groups performed a mannequin-based technical skills emergency cricothyroidotomy test twice and were assessed by a blinded rater using a structured assessment tool that included time, positioning, palpation, appropriate employment of instruments, and stepwise progression. After 3 months of non-training, participants completed identical tests of retention. RESULTS: A total of 54 anesthesiologists were included from three hospitals in the Region of Southern Denmark. Thirty-seven percent of the participants had received skills training in emergency cricothyroidotomy in the prior 12 months. The intervention group (N = 27) performed better in the initial tests, with a mean time of 51.5 s (SD = 10.82), a total score per minute of 15.9 points (SD = 4.91), and 93% passing both initial tests compared to the control group (N = 27) with a mean time of 76.8 s (SD = 35.82), a total score per minute of 6.6 (SD = 4.68) and only 15% passing both initial tests. The intervention group managed to retain overall performance in retention tests in terms of performance time (48.9 s, p = .26), total score per minute (13.6 points, p = .094), and passing the tests (75%, p = .059). CONCLUSION: Exposure to simulation-based brush-up training in emergency cricothyroidotomy improved anesthesiologists' technical performance and was overall retained after 3 months. Some loss of skill concerning specific items was observed, highlighting the need for regular training in emergency cricothyroidotomy. Simulation-based training should be prioritized to improve and maintain technical skills in infrequent high-stakes procedures.