OBJECTIVE: To evaluate the recurrence rates and patterns of failure in patients with stage I endometrial carcinoma after surgical staging without adjuvant therapy. METHODS: Medical records of 229 patients with stage I endometrial carcinoma, treated with surgery alone between 2002 and 2010 at Siriraj Hospital were retrospectively reviewed. The primary objective of this study was recurrence rates. The secondary objectives were patterns of failure, disease-free survival, overall survival, and prognostic factors related to outcomes. RESULTS: During median follow-up time of 53.3 months, 11 recurrences (4.8%) occurred with a median time to recurrence of 21.2 months (range, 7.7 to 77.8 months). Vaginal recurrence was the most common pattern of failure (8/11 patients, 72.7%). Other recurrences were pelvic, abdominal and multiple metastases. Factors that appeared to be prognostic factors on univariate analyses were age and having high intermediate risk (HIR) (Gynecologic Oncology Group [GOG] 99 criteria), none of which showed significance in multivariate analysis. The recurrence rates were higher in the patients with HIR criteria (22.2% vs. 4.1%, p=0.013) or patients with stage IB, grade 2 endometrioid carcinoma (9.4% vs. 4.3%, p=0.199). Five-year disease-free survival and 5-year overall survival were 93.9% (95% CI, 89.9 to 5.86) and 99.5% (95% CI, 97.0 to 99.9), respectively. CONCLUSION: The patients with low risk stage I endometrial carcinoma had excellent outcomes with surgery alone. Our study showed that no single factor was demonstrated to be an independent predictor for recurrence.