Both irinotecan and oxaliplatin have demonstrated important clinical activity in metastatic colorectal cancer. Although they appear to have similar activity in metastatic disease, only oxaliplatin has demonstrated efficacy in the adjuvant setting. Despite a survival advantage of single agent irinotecan in the second-line metastatic setting and a survival advantage for irinotecan added to first-line metastatic treatment, irinotecan has failed to show a survival or disease-free survival benefit in the adjuvant setting, and at the present time there is no role for irinotecan in the adjuvant treatment of colon cancer. In contradistinction, the addition of oxaliplatin to 5-fluorouracil/leucovorin has improved disease-free survival in two large randomized adjuvant trials. Data for overall survival in these trials have not yet demonstrated statistical significance but are expected to with maturation. Oxaliplatin/5-fluorouracil/ leucovorin should, therefore, be regarded as a reference standard for adjuvant therapy.