Between 1974 and 1991, 621 patients with endometrial cancer were treated with hysterectomy without any preoperative treatment. Subsequent pathological examinations revealed that 92 cases had no myometrial invasion. Clinicopathological analysis was carried out in the 92 patients. The results are as follows: 1. Complete surgery was carried out in all cases except one case with intraperitoneal dissemination. The relapse rate in the 91 cases was 2.2% (2/91). The 2 cases with recurrence had grade 1 (G1) and grade 2 (G2) adenocarcinoma and both cases manifested local recurrence. 2. Of 70 cases treated with pelvic lymphadenectomy, two cases (2.9%) with G1 adenocarcinoma exhibited a single node metastasis. The metastatic site was an external iliac lymph node in both cases. Despite the lymph node metastasis, the 2 cases have exhibited no relapse. 3. None of the 92 cases showed any evidence of adnexal metastasis. The positive rate of peritoneal cytology was 13.4% (9/67). Except for one case with peritoneal dissemination who also had positive peritoneal cytology, 8 cases with positive peritoneal cytology have not developed recurrence. This study showed that some endometrial cancer patients without myometrial invasion manifest recurrence, peritoneal dissemination or lymph node metastasis. It is therefore considered that lymphadenectomy and careful follow-up are necessary in every case of endometrial cancer, even in G1 cases without myometrial invasion.