Objectives: In the prehospital setting, endotracheal intubation (ETI) is sometimes required to secure a patient's airways. Emergency ETI in the field can be particularly challenging, and success rates differ widely depending on the provider's training, background, and experience. Our aim was to evaluate the ETI success rate in a resident-staffed and specialist-physician-supervised emergency prehospital system. Methods: This retrospective study was conducted on data extracted from the Geneva University Hospitals' institutional database. In this city, the prehospital emergency response system has three levels of expertise: the first is an advanced life-support ambulance staffed by two paramedics, the second is a mobile unit staffed by an advanced paramedic and a resident physician, and the third is a senior emergency physician acting as a supervisor, who can be dispatched either as backup for the resident physician or when a regular Mobile Emergency and Resuscitation unit (Service Mobile d'Urgence et de Réanimation, SMUR) is not available. For this study, records of all adult patients taken care of by a second- and/or third-level prehospital medical team between 2008 and 2018 were screened for intubation attempts. The primary outcome was the success rate of the ETI attempts. The secondary outcomes were the number of ETI attempts, the rate of ETI success at the first attempt, and the rate of ETIs performed by a supervisor. Results: A total of 3275 patients were included in the study, 55.1% of whom were in cardiac arrest. The overall ETI success rate was 96.8%, with 74.4% success at the first attempt. Supervisors oversaw 1167 ETI procedures onsite (35.6%) and performed the ETI themselves in only 488 cases (14.9%). Conclusion: A resident-staffed and specialist-physician-supervised urban emergency prehospital system can reach ETI success rates similar to those reported for a specialist-staffed system.