Attention has been paid to secondary carnitine deficiency in children. However, secondary carnitine deficiency in pediatric patients has been reported repeatedly. In this study, the questionnaire survey of medical worNers on secondary carnitine deficiency in children was conducted. In the study, 125 individuals including 22 pediatricians, 18 non-pediatric doctors, 80 nurses, and 5 pharmacists in our hospital were enrolled. As a result, the response rate to secondary carnitine deficiency in children was insufficient. In addition, there was a statistically significant difference in the response rate between pediatricians and other medical workers. Pediatric practice consists of not only pediatricians but also other medical workers. Therefore, it is important that all medical staffs participating in pediatric practice deepen their knowledge of secondary carnitine deficiency and thereby prevent the deficiency.