Background: Small cell carcinoma of the endometrium is extremely rare. There is no reported case of secondary small cell carcinoma of the endometrium after concurrent chemoradiotherapy for cervical cancer. Case Report: A 48-year-old woman was diagnosed with squamous cell carcinoma of the cervix Stage IIIB (T3bN0M0) and treated by concurrent chemoradiotherapy. After five years and nine months’ post-treatment, the woman was diagnosed with small cell carcinoma of the endometrium Stage IIIA (pT3aNXM0). Although the patient received chemotherapy combining paclitaxel and carboplatin postoperatively, she developed a recurrence with pelvic tumor three months after operation. After recurrence, she received one course of chemotherapy combining cisplatin and irinotecan. Although a remarkable reduction of recurrent tumor was found as autopsy findings, she died of disease two months after this chemotherapy. Conclusion: In case of small cell carcinoma of the endometrium, chemotherapy regimen used for small cell lung cancer such as chemotherapy combining cisplatin and irinotecan should be considered.