OBJECTIVE: The aim of this study is to evaluate the clinical usefulness of preoperative CA 125 levels in determining the need for lymphadenectomy in patients with endometrial carcinoma. METHODS: CA 125 levels were measured in 100 patients diagnosed with endometrial carcinoma who underwent surgery at Kangnam St. Mary's Hospital between October 1992 and 0ctober 2002. Statistical analysis was performed using the Mann-whitney U test and chi2-Fisher's exact test. RESULTS: Univariate analyses showed that elevated CA 125 levels were significantly correlated with an advanced stage, increasing depth of myometrial invasion, cervical invasion, adnexal involvement, high grade hystology and lymph node metastases (p<0.05). CONCLUSION: Our data provide an evidence that the elevation of preoperative CA 125 levels can be considered as a predictor for full pelvic lymphadenectomy in the surgical staging of endometrial cancer.