Primary pulmonary rhabdomyosarcoma (RMS) in the pediatric population is a rare entity. A 5-month-old boy initially treated for pneumonia was proven to have a primary pulmonary RMS, which was resected via thoracotomy. After a course of chemotherapy following the Children's Oncology Group low-risk RMS protocol (ARST0331), a restaging chest computerized tomography scan showed local recurrence, which was also resected by open thoracotomy. The patient is currently undergoing local radiotherapy and salvage chemotherapy regimen. This patient is the youngest reported to date with this entity. The prognostic significance of his young age and the morphologic findings of his tumor are unclear.