Abstract. The present study reports a rare case of radiation recall pneumonitis attributed to ifosfamide that was used as a single antitumor agent for a recurrent malignant soft tissue tumor, arising from the chest wall. A 74-year-old man, who had a mass in his right upper chest wall, underwent surgical excision under the diagnosis of chronic expanding hematoma. He was referred to the present hospital with a recurrent tumor as the excised tumor was diagnosed as undifferentiated high-grade sarcoma. The extension of the tumor following previous surgery was aggressive and the tumor margins were unclear on magnetic resonance imaging. Wide excision was done with adequate margins for the new recurrent tumor as it was difficult to set sufficient tumor margins following the previous surgery. Radiotherapy (60 Gy) on his right subclavicular area and chemotherapy with ifosfamide (3.5 g x 4 days/cycle) was started 1 month following surgery to control the growth of residual tumors and to prevent metastases. The third cycle of chemotherapy with ifosfamide (3 g x 4 days) was started 80 days following the final surgery and 15 days following termination of radiotherapy. Following administration, he felt short of breath and dyspnea gradually increased. This condition was diagnosed as interstitial pneumonitis induced by ifosfamide following radiotherapy. Although corticosteroid pulse therapy was performed, he died due to respiratory failure. To the best of the author's knowledge, this is the first case report of radiation recall pneumonitis induced by ifosfamide used as a single anti-tumor agent. Caution is needed when ifosfamide is planned for patients who have undergone previous radiotherapy to the chest.