Objective : This study was performed to determine the safety and outcome of concurrent chemoradiotherapy (CCRT) and adjuvant chemotherapy with temozolomide for Korean patients with a newly diagnosed glioblastoma. Methods : Patients were recruited from four institutions between 2004 and 2007. The patients received fractionated focal irradiation in daily fractions of 2 Gy given 5 days per week for 6 weeks and daily temozolomide, followed by 6 cycles of adjuvant temozolomide. The primary endpoint was overall survival (OS) and the secondary endpoints were progression-free survival (PFS), response, and safety. Results : A total of 103 patients were enrolled in this study. Ninety-six patients (93%) completed the CCRT and 54 patients (52%) received 6 cycles of adjuvant temozolomide. The response rate was 73% (53/73) and the tumor control rate was 92% (67/73). Of the 96 patients who completed the CCRT, the median OS was 18.0 months and the 1- and 2-year OS rates were 74 and 38%, respectively. The median PFS was 10.0 months and the 1- and 2-year PFS rates were 33 and 16%, respectively. The only significant prognostic factor of survival was the extent of surgical resection (p<0.05). CCRT resulted in grade 3 or 4 hematologic toxic effects in 8% of patients. No opportunistic infections were noted. Conclusion : This study is the first prospective multi-institutional report of CCRT and adjuvant chemotherapy with temozolomide for patients with a newly diagnosed glioblastoma in Korea. The current protocol may prolong the survival of Korean patients with a glioblastoma and may be tolerable in terms of toxicity.