Primitive Neuroectodermal Tumor (PNET) is a small round cell malignancy arising in bone and soft tissue. With the progress of immunohisto-chemical and ultrastructural studies, the tumor has getting attention. We report a rare case of PNET arising from rib. A 19-year-old man was admitted to our hospital complaining of chest and back pain. The tumor arised from 5th rib and en bloc resection was performed. Pathological diagnosis was PNET. After the operation, he is doing well, except being treated with chemotherapy (T9-protocol).