Aim of the study: Inaccurate lymph node staging affects treatment planning and may contribute to worse prognosis. A retrospective study was performed to confirm this hypothesis. Materials and methods: Data about patients diagnosed with stage I–III endometrial cancer between January 1, 2008 and December 31, 2009 (cases with multiple primary tumors were excluded) was extracted from cancer register of Kyiv City Clinical Oncology Centre. Hypothesis: The absence of lymphadenectomy in a patient with apparent early stage endometrial cancer, but with undiagnosed lymph node metastases may lead to understaging and undertreatment with worse prognosis and outcomes. Cancer-specific survival was the primary outcome. Results: From 564 patients assessed for eligibility, 61 were excluded. Cancer-related death was reported in 76 cases: 39 stage I, 14 – stage II, and 23 – stage III patients. Median cancer-specific survival was 27 months for stage I, 14 months for stage II, and 19 months for stage III (p = 0.01). Three-year cancer-specific survival rate was 33.3% for stage I, 0% for stage II, and 17.4% for stage III. Intergroup analysis showed a statistically significant difference in survival between stage I and stage II patients (p = 0.005), but there was no statistically significant difference in survival between stage III and stage I or II patients (p = 0.072 and p = 0.151, respectively). Conclusions: The same rates of cancer-specific survival may indicate that the presented cases of apparently early stage endometrial cancer were understaged and consequently undertreated. Further studies in larger groups of patients are needed.