Of 41 women with FIGO stage I endometrial adenocarcinoma who underwent staging paraaortic lymphadenectomy and paraaortic node biopsy, 6 (14.6%) had metastasis to the paraaortic lymph nodes. None of the 11 patients with grade 1 carcinoma had paraaortic node metastasis; 13.6% of grade 2 carcinomas and 37.5% of grade 3 carcinomas were associated with paraaortic node metastasis. None of the 8 patients with tumor limited to the endometrium had paraaortic metastasis, and only 4.5% of the patients with superficial myometrial invasion had metastasis to the paraaortic lymph nodes. However, this increased to 45.5% for tumors deeply invading the myometrium. Of the patients with paraaortic node metastasis, 83.3% had either grade 3 tumors or deep myometrial invasion. Only 1 patient in the study with paraaortic node metastasis did not have either a grade 3 carcinoma or a tumor deeply invading the myometrium. Because of the high incidence of paraaortic node metastasis with grade 3 tumors or deep myometrial invasion, surgical staging by paraaortic lymphadenectomy or lymph node biopsy is recommended at the time of primary surgery for early endometrial adenocarcinoma.