PURPOSE: To evaluate the impact of postoperative radiotherapy on loco-regional failure in patients with vulvar carcinoma and to determine the treatment strategy for inguinal lymph nodes. MATERIALS AND METHODS: Sixty-six patients who received treatment for primary vulvar carcinoma at Seoul National University Hospital, from October 1979 through June 2004, were retrospectively analyzed. Sixteen patients were excluded from the analysis due to the following reasons: distant metastases in two patients; palliative intent for six patients; previous radiotherapy given to the pelvis in three patients; follow-up loss after surgery for four patient; insufficient medical records for one patient. Of 50 eligible patients, 35 were treated with surgery alone (S), ten were treated with surgery followed by radiotherapy (S+RT), and five were treated with radiotherapy alone. RESULTS: The 5-year overall survival (OS) and disease-free survival (DFS) rates of all patients were 91% and 78%, respectively. Twelve patients (26%) experienced treatment failures and the sites of initial failure were as follows: a primary site in eight patients; regional lymph nodes in three patients; the lung in one patient. Although risk factors for failure were more common in the S+RT group than the S group of patients (p<0.05), the DFS rates were similar for the two groups (5-year DFS rates, 78% vs. 83%, p=0.66). The incidences of occult lymph node metastases was 10%. Ten of 31 patients with clinically negative lymph nodes did not received inguinal lymph node dissection, but no patient experienced regional failure. CONCLUSION: Postoperative radiotherapy may have a potential benefit for patients with risk factors for failure. The omission of inguinal dissection or elective radiotherapy to the inguinal lymph nodes may be considered in low-risk patients with clinically negative lymph nodes.