Rhabdomyosarcoma (RMS) is a well-described cancer in Li-Fraumeni Syndrome (LFS), resulting from germline TP53 pathogenic variants (PVs). RMS exhibiting anaplasia (anRMS) have been associated with a high rate of germline TP53 PVs. This study provides an updated estimate of the prevalence of TP53 germline PVs from a large cohort of patients (n=239) enrolled in five Children’s Oncology Group (COG) clinical trials. Although the prevalence of germline TP53 PVs in anRMS patients in this series is much lower than previously reported, this prevalence remains significantly elevated. Germline genetic evaluation for TP53 PVs should be strongly considered in patients with anRMS.