Background: Oxaliplatin-containing regimen is a standard adjuvant chemotherapy for resected stage III colon cancer. Oxaliplatin-containing regimens were investigated for their efficacy in patients with resected stage III colon cancer in MOSAIC and XELOXA studies. Since these two international randomized studies were performed outside of Japan, we conducted a phase II study (NORTH/HGCSG1003) to assess the efficacy and safety of FOLFOX as adjuvant chemotherapy in Japanese patients (pts) with resected stage III colon cancer (UMIN ID: 000004590). Methods: This phase II study enrolled patients with resected stage III colon cancer. Patients received 12 biweekly cycles of FOLFOX4 or mFOLFOX6. Sample size was determined to be 243 pts. Primary endpoint was DFS. Secondary endpoints included overall survival (OS) and safety. Results: From September 2010 to March 2013, 273 pts were enrolled at 28 institutions. Safety analysis included 265 patients who received FOLFOX. Patients characteristics were as follows: median age, 65 (33-84); male/female: 131/134; PS 0/1:258/7; stage IIIA/IIIB/IIIC: 37/197/31; colon/rectosigmoid: 214/51. The most common grade 3-4 adverse events were neutrophil count decreased (48.1%), platelet count decreased (2.3%), and allergic reaction (1.5%). The incidence of peripheral sensory neuropathy (PSN) was 41.9% (grade 1), 38.1% (grade 2), and 6.4% (grade 3). PSN tended to be serious depending on the cumulative dose of oxaliplatin (table 1). Median cumulative dose of oxaliplatin at which PSN occurred were as follows: grade 1; 170 mg/m2, ≥ grade 2; 850 mg/m2, ≥ grade 3; (-). The median number of cycles of chemotherapy was 12, and the completion treatment rate was 80.4%. There was no treatment-related death. Conclusions: In Japanese patients with stage III colon cancer, FOLFOX is a well-tolerable regimen as adjuvant chemotherapy. Clinical trial information: 000004590.