Background: The stresses of starting a new job can make anyone feel tired and inefficient. In health care, this may impair the ability to learn at a time when there is most to learn, and increase the risk of error in a context where errors may lead to patient harm. Aim: The aim of this study was to understand issues which influence anesthesia trainees’ transition to a pediatric setting. Methods: This qualitative study utilized in-depth semi-structured interviews to gather data from 31 anesthesia trainees who had commenced work at a tertiary children's hospital between 4 and 6 weeks previously. Data were examined using thematic analysis. Results: Two key themes were identified: feeling ineffective, which appeared to have both a cognitive component (feeling disoriented) and an emotional component (feeling useless), and feeling anxious or afraid. Trainees found the pediatric environment highly unfamiliar, which made them feel disoriented, inefficient, and at times incompetent. Many experienced difficulty identifying a useful role in a highly specialized area of practice, leading to loss of identity as an expert clinician. Many described an ever-present fear of making an anesthetic error or being unable to manage a rapidly evolving clinical situation. Some trainees developed a negative mindset, which was reinforced by subsequent perceived failures. Overall, these experiences impeded trainees’ ability to concentrate and learn. Conclusions: The impact of disorientation and anxiety on anesthesia trainees as they adapt to a highly specialized clinical environment such as a children's hospital should not be underestimated. Study findings illustrate the importance of helping new trainees to feel less afraid, more useful, and more realistic in assessing their own performance during the transition period.