We report two cases of hypopharyngeal cancer that developed purulent spondylitis after radiation therapy (RT). Case 1 was a 77-year-old woman who presented with neck pain and restricted backbending ability. She had undergone RT (70 Gy, combined with cetuximab) for cT3N0M0 hypopharyngeal cancer. Nine months after RT, she was diagnosed as having purulent spondylitis from the findings on MRI. The purulent spondylitis rapidly improved with conservative antibiotic (ceftriaxone) therapy for 7 days. Case 2 was a 57-year-old man who presented with dysphagia. He had undergone RT (70 Gy, combined with docetaxel) for cT2N0M0 hypopharyngeal cancer. Seven months after the RT, he was diagnosed as having purulent spondylitis based on the radiological (MRI) and histopathological findings. We performed surgical debridement and reconstruction of the lesions, as the purulent spondylitis proved refractory to antibiotic (tazobactam/piperacillin) therapy for 14 days. At four years 6 months after the surgery, the lesions remained controlled and no recurrence was observed. Although purulent spondylitis occurring after RT is rare, it is important to consider this potentially fatal disease as one of the serious late complications after RT.