BACKGROUND: Colorectal cancer is the third leading cancer worldwide (INCA) with nearly 1.2 million cases and about 630,000 deaths expected in 2007 (ACS, 2007). In Brazil, it is estimated 28,110 new cases in 2010 (INCA, 2010). For patients with stage III colon cancer, the benefits from fluorouracil (5-FU) based adjuvant chemotherapy are well established and the combination regimens including a fluoropyrimidine + oxaliplatin are the current standard of care. OBJECTIVES: To compare costs of XELOX with FOLFOX-4 as adjuvant treatment for stage III colon cancer under Brazilian private payer perspective. METHODS: Both regimens demonstrated to significantly improve disease-free-survival when compared to 5-FU/LV for adjuvant treatment of stage III colon cancer (MOSAIC and XELOXA trials). In the absence of head-to-head trials comparing both regimens, an indirect comparison using Butcher approach (Butcher, 1997) was conducted. No difference was found regarding efficacy of regimens (XELOX vs FOLFOX-4 in disease-free-survival: HR 1.03, 95%CI 0.81, 1.29), therefore, a cost-minimization analysis was used. A modified Delphi panel identified local practices to manage severe adverse events (SAEs) of each scheme. Only direct costs were considered for a patient with 1.7m². Drug prices were obtained from official public sources (Kairos Magazine, April 2010) and administration costs from medical society physicians fee list (CBHPM2008, v.5). Time-horizon was 6 months according to clinical recommendations: 8 cycles for XELOX and 12 for FOLFOX-4. Discounting  wasn’t applied. RESULTS: XELOX is less costly than FOLFOX-4 ($Brz49,862 vs. $Brz57,846). XELOX has higher acquisition costs which is offset by savings in medical resource utilization.  Mean acquisition costs for XELOX were R$4,185 higher than with FOLFOX-4, but costs to treat SAEs and administration costs were $Brz12,169 higher for FOLFOX-4. One-way sensitivity analysis confirmed the robustness of results. CONCLUSIONS: Findings suggest XELOX as a cost-saving therapy for the adjuvant setting under the private payer perspective in Brazil when compared to FOLFOX-4.