Infant observation is an integral part of training in child and adult psychotherapy. Psychotherapy trainees and qualified health professionals may benefit from using psychoanalytic observations in other settings. This study aimed to explore the effect on these professionals of observational experiences during their training. The study comprised of a systematic literature review with pre-specified eligibility criteria. It used a systematic search strategy and provided a summary of the literature on the topic. The effects on the trainee and professional were related to the role undertaken by them as observers during the observation and the use of the observer’s countertransference in furthering understanding of the observation. Overall trainees found observation experiences useful and effective for training.