We evaluated the concentrations of human epididymis secretory protein E4 (HE4) and Ca-125 in relation to clinicopathologic features in patients with endometrial cancer and premalignant endometrial lesions. Women with abnormal uterine bleeding (n = 167) who underwent endometrial sampling were divided into four groups. Group 1: endometrial cancer (n = 68), group 2: atypical endometrial hyperplasia (n = 12), group 3: endometrial hyperplasia without atypia (n = 39) and group 4: controls (n = 48). Women with endometrial cancer exhibited higher concentrations of HE4 levels than controls (91.4 pmol/L vs. 46.2 pmol/L, p < 0.001). HE4 levels were significantly higher in patients with lymphatic involvement, deep myometrial invasion, lymphovascular space involvement and non-endometrioid histology (p < 0.001). The sensitivity, specificity, positive and negative predictive values for HE4 in detecting endometrial cancer were 72.7%, 84.4%, 80% and 78.4%, respectively. Preoperative HE4 levels are more elevated in women with endometrial cancer than those with benign endometrium as well as in women with prognostic high-risk factors with endometrial cancer. HE4 may be used as an additional marker in combination with other clinicopathologic features for planning the treatment.