Psychosomatic disorders are influenced by psychosocial factors such as interpersonal relationships. Coping behaviors, especially in frustrating situations, reflect a patient’s ability to cope with stress, and it is important to assess these behaviors for the treatment of psychosomatic diseases. This study aimed to clarify the interpersonal relationships and coping behaviors of pediatric patients with psychosomatic diseases during frustrating situations simulated using the Rosenzweig Picture-Frustration study. This retrospective study included 126 patients (41 male, 85 female) with an average age of 12.9 (6-16) years who were consulted at the Department of Pediatric Psychosomatic Medicine at Okayama University Hospital from 2013 to 2018 and underwent the P-F study. Each score was compared with a standardization sample. The mean group conformity rating did not differ significantly between the participants and healthy children. Compared with healthy children, those with psychosomatic diseases were less likely to explain their perspective. The children with psychosomatic disorders responded to frustrating situations in a sensible and age-appropriate manner. However, they were less likely to respond by explaining their perspective to protect themselves.