Objectives To investigate short-term and long-term effectiveness of simulation training to acquire a structured Airway Breathing Circulation Disability Exposure (ABCDE) approach for medical emergencies; and to examine which skills were learnt and maintained best. Design An observational study with a 3-4 months follow-up. Setting Skills center of the University Medical Center Groningen. Participants Thirty voluntary participants (21 females and 9 males; 27±2.77 years) of a simulation-based course. Intervention A 2-day ABCDE-teaching course for residents and non-residents. The course encompasses 24 simulations in which participants perform primary assessments of acute ill patients. Video recordings were taken of each participant performing a primary assessment, before (T1), directly after (T2) and 3-4 months after the intervention (T3). Main outcome measures Physicians' performance in the ABCDE primary assessment at T1, T2 and T3. Two observers scored the primary assessments, blinded to measurement moment, using an assessment form to evaluate the performance with regard to skills essential for a structured ABCDE approach. The Friedman and Wilcoxon signed-rank test were used to compare physicians' performances on the subsequent measurement moments. Results The mean ranks on the total primary assessment at T1, T2 and T3 were 1.14, 2.62 and 2.24, respectively, and were significantly different, (p<0.001). The mean ranks on the total primary assessment directly after the course (T2 vs T1 p<0.001) and 3-4 months after the course (T3 vs T1 p<0.001) were significantly better than before the course. Certain skills deteriorated during the follow-up. Strikingly, most skills that decrease over time are Crew Resources Management (CRM) skills. Conclusion A course using simulation training is an effective educational tool to teach physicians the ABCDE primary assessment. Certain CRM skills decrease over time, so we recommend organising refresher courses, simulation team training or another kind of simulation training with a focus on CRM skills.