OBJECTIVE To evaluate the impact of preoperative leukocytosis among patients with endometrial carcinoma. METHODS The medical records of all patients that underwent surgical treatment for endometrial carcinoma between January 2005 and December 2010 were retrospectively reviewed. Patients were separated into two groups based on the presence or absence of preoperative leukocytosis (WBC ≥ 10,000 cells per μl). The groups were then compared with respect to pathologic findings, progression-free survival and overall survival. RESULTS 1144 patients were identified, 156 (13.6%) with preoperative leukocytosis and 988 (86.4%) without leukocytosis. The leukocytosis group had a greater percentage of patients with stage 3 (15.4% vs. 9.8%, crude p=0.02) and 4 (7.1% vs. 3.0%, crude p=0.007) disease. Leukocytosis was associated with a greater mean tumor size (4.4 vs. 3.4 cm, p=0.0002) and a greater percentage of patients with cervical stromal involvement (14.8% vs. 8.7%, crude p=0.02), adnexal involvement (14.1% vs. 7.5%, crude p=0.007) and lymphvascular space invasion (24% vs. 16.3%, crude p=0.02). On multivariate analysis, mean tumor size (OR, 95% CI; 1.10, 1.02-1.18) remained significantly associated with preoperative leukocytosis. There was no difference between groups, with respect to time to recurrence. However, leukocytosis was independently associated with an increased risk of death (HR, 95% CI; 1.69, 1.07-2.68). CONCLUSIONS Preoperative leukocytosis, among endometrial cancer patients, was independently associated with increasing tumor size and independently imposed an increased risk of death.