The objective of this study was to compare FIGO 1988 and 2009 endometrial carcinoma staging systems in terms of patient distribution and efficacy in predicting prognosis in patients treated with surgery and adjuvant radiotherapy (RT). Medical records of 351 patients treated between 1994 and 2009 were retrospectively analyzed. Adjuvant RT was in the form of vaginal cuff brachytherapy (BRT) in patients with uterine confined disease and risk factors, whereas high-risk patients received risk-adapted external pelvic RT. The median follow-up time was 55 months (range, 2.5-133 months). Five-year overall (OS) and disease-free survival (DFS) for the entire group was 83 and 88%, respectively. Stage migration was observed in 188 (54%) patients. Stage migration generally did not cause any significant effect in OS and DFS rates. However, 5-year OS and DFS for stage I patients with positive peritoneal cytology was significantly lower than the other patients with negative cytology in FIGO 2009 system. The survival curves overlapped for stage IA, IB and II in the new staging system. On the other hand, the division of stage IIIC as IIIC1 and IIIC2 significantly affected the prognosis. Patients with stage IIIC2 tumor had 40% OS and 48% DFS rates compared to 69 and 66% in stage IIIC1 patients (p = 0.002). The major improvement of FIGO 2009 seems to be the subclassification of stage IIIC disease into IIIC1 and IIIC2. The positivity of peritoneal cytology per se seems to have an influence in prognosis in our cohort. To withdraw the positive cytology from staging may mislead the prognosis estimation in these patients and lead to undertreatment.