PURPOSE: Twenty-year follow-up results of two pioneering randomized controlled trials have demonstrated equal patient survival after mastectomy and breast conservation therapy. The use of breast conservation therapy has undoubtedly provided substantial progress towards a better quality of life for women with breast cancer. Outcomes of breast conservation therapy performed at Asan medical center were retrospectively reviewed and analyses were performed to determine significant risk factors of local recurrence. METHODS: A total of 578 women with stage I, stage II or stage III breast cancer were treated with conservative surgery and radiation therapy between January 1997 and December 2002. Outcomes of local recurrence and survival were recorded. RESULTS: During a median follow-up of 54.1 months, 21 patients (3.6%) developed local recurrence as first event and 10 patients (1.7%) developed regional recurrence and 19 patients (3.3%) developed systemic recurrence. Univariate analysis of the prognostic factors determined that age (p=0.005), nuclear grade (p=0.013), estrogen receptor negativity (p=0.008), lymphovascular invasion (p=0.009), progesterone receptor negativity (p=0.016) and lack of hormone therapy (p=0.005) were statistically significant factors associated only with locoregional recurrence. Results of multivariate analysis determined that lymphovascular invasion (p=0.045) strongly independent predictors for local recurrence. CONCLUSION: Age, nuclear grade, estrogen receptor negativity, lymphovascular invasion, progesterone receptor negativity and lack of hormone therapy were associated with local recurrence after Breast conserving surgery. The lymphovascular invasion was the strongest independent risk factors for local recurrence.