To report the results of a planned safety analysis from a phase III trial comparing capecitabine plus oxaliplatin (XELOX) with bolus fluorouracil/leucovorin (FU/LV) as adjuvant therapy for stage III colon cancer. Patients with stage III colon carcinoma were randomly assigned to receive either XELOX (intravenous oxaliplatin plus oral capecitabine; 3-week cycle for eight cycles) or standard intravenous bolus FU/LV administered as the Mayo Clinic (Mayo; Rochester, MN) or Roswell Park (RP; Buffalo, NY) regimen for a similar length of time. A total of 1,886 patients were randomly assigned. The safety population comprised 1,864 patients, of whom 938 received XELOX and 926 received FU/LV. Most treatment-related adverse events (AEs) occurred at similar rates in both treatment arms. However, patients receiving XELOX experienced less all-grade diarrhea, alopecia, and more neurosensory toxicity, vomiting, and hand-foot syndrome than those patients receiving FU/LV. Compared with Mayo, XELOX showed fewer grade 3/4 hematologic AE and more grade 3/4 gastrointestinal AE. Compared with RP, XELOX showed less grade 3/4 gastrointestinal AE and more grade 3/4 hematologic AE. As expected grade 3/4 neurosensory toxicity and grade 3 hand-foot syndrome were higher with XELOX. Treatment-related mortality within 28 days from the last study dose was 0.6% in the XELOX group and 0.6% in the FU/LV group. XELOX has a manageable tolerability profile in the adjuvant setting. Efficacy data will be available within the next 24 months.