Psychological symptoms are often seen in pediatric patients who are confined to a germ-free unit while undergoing bone marrow transplants. The Picture-Frustration Study( P-F study) was performed at the outpatient clinic before admission to the germ-free unit. After admission to the germ-free unit, the patients were interviewed once a week in the germ-free unit, and their mental symptoms were recorded in their clinical records. Condition of anxiety, unresponsiveness, resistance to treatment, and aggression have been noted in pediatric patients below the age of 18 in the Tokai University Hospital. Insomnia, appetite loss, anxiety, unresponsiveness showed a significant correlation with the patient's age. Forty-seven children were given the P-F study before entering the germ free unit. Anxiety, depression, and unresponsiveness correlated significantly with several items in the P-F study. The results of P-F study are useful in predicting the appearance of psychological or physical symptoms of patients confined to the germ-free unit.