The present study aimed to clarify the occurrence rate of lymphedema and prognosis in patients with endometrial cancer according to sentinel lymph node biopsy alone with intraoperative histopathological examination. The study included 45 consecutive patients with endometrial cancer treated at Tohoku University Hospital between October 2014 and August 2017. All patients had endometrial carcinoma with endometrioid histology Grade 1 or Grade 2 confirmed by biopsy and stage I on magnetic resonance imaging and/or computed tomography at their preoperative evaluation. Sentinel lymph node detection was performed by radioisotope and dye. Patients who were diagnosed intraoperatively as negative for sentinel lymph node metastasis did not undergo further systematic pelvic lymphadenectomy. The occurrence rate of lymphedema and prognosis was evaluated. Bilateral sentinel lymph nodes were detected in 44 of 45 patients (97%). Forty-three patients underwent sentinel lymph node biopsy alone, and only two patients underwent systematic lymphadenectomy. Sentinel lymph node metastases were detected in one patient intraoperatively and two patients postoperatively as ITCs. No patients experienced recurrence. New symptomatic lower-extremity lymphedema was identified in one of 43 patients (2.3%) who underwent sentinel lymph node biopsy alone. Sentinel lymph node biopsy alone with intraoperative histopathological diagnosis appears to be a safe and effective strategy to detect lymph node metastasis and to reduce the number of patients with lower-extremity lymphedema among patients with endometrial cancer.