Background. Large-scale surveys of complementary traditional Chinese medicine (TCM) use in pediatric cancer patients are lacking. The aim of our study was to investigate the use of TCM in pediatric cancer patients. Methods. We analyzed cancer patients younger than 18 years (n = 12 965) who were registered in the National Health Insurance Research Database in Taiwan between 2001 and 2011. Patients were categorized into TCM or non–TCM users based on their use of TCM. Results. In Taiwan, 8086 (62.4%) children with cancer sought TCM treatment at some point. Children in older age groups, including school-aged children and adolescents, were more likely to use TCM. There was no significant difference in the distributions of gender and urbanization. The 3 most common diseases for which TCM users visited the clinic were neoplasm (33.2%), respiratory system disease (32.9%), and infectious disease (8.86%). The most commonly utilized TCM therapy was Chinese herbal remedies. Patients who had comorbid conditions such as allergic rhinitis, dyspepsia, disorders of menstruation, and disease of the musculoskeletal system and connective tissue tended to visit TCM clinics. Conclusions. Adjunctive TCM use is not low in Taiwanese children with cancer. Further studies to investigate the efficacy and safety of TCM in children with cancer are warranted.