The current shortage of child and adolescent mental health specialists in Europe and around the world, coupled with an increasing mental health burden among young people poses significant challenges that future child and adolescent psychiatry (CAP) training programs must address. Promoting the use of standardized assessments (SA) has the potential to improve both efficiency and quality of patient care as well as resident training programs. This study aimed to characterize a sample of CAP trainees (residents and assistant psychologists) in Switzerland and evaluate their SA use as well as their corresponding skills and attitudes. The project was launched at the Swiss CAP Association Residents' Day 2022 in Zurich, where the development of a national survey was initiated. The survey was subsequently refined and distributed to all CAP training facilities in Switzerland. The final sample included 73 residents and 121 assistant psychologists. The majority of trainees from both groups reported being interested in using SA and convinced of their clinical usefulness. Common reasons for using SA in clinical practice were to support objectivity, structure clinical interviews, and address sensitive topics with patients. Participants' SA use varied by type of psychotherapy training but did not differ by type of institution (university vs. non-university hospital) or academic degree. Self-rated ability to administer SA correlated positively with SA training opportunities. A frequently reported use barrier was the lack of SA translations. Based on our findings, CAP would benefit from teaching and promoting SA as a seminal, evidence-based practice in clinical and training program contexts.