Background: Adjuvant treatment of stage III colon cancer represents a significant economic burden for the German health care system. The available chemotherapy regimens have significantly different medical and economic profiles. Methods: A modeling study based on published clinical trials was performed to assess costs of 5 different regimens (Mayo Clinic, LV5FU2, FOLFOX-4, Xelox, Capecitabine) from the perspective of the statutory sickness funds. Costs were calculated based on the assumption that patients were treated exactly according to a standardized clinical pathway. Results: Total costs are highest for FOLFOX-4 (H22,034/patient) and Xelox (H21,411). Lowest costs of the oxaliplatin-free treatments are associated with capecitabine (H4,935), followed by the Mayo Clinic (H6,426) and LV5FU2 protocols (H8,336). The main driver of costs in all instances is drug acquisition (90% of total costs), whereas costs of diagnostics or complications have no major impact (0.5–2%). Conclusions: In Germany, FOLFOX-4 is the most effective but also the most expensive treatment and represents the current standard. Xelox emerges as a slightly less costly alternative when oral treatment is preferred. For patients not able to tolerate oxaliplatin-based therapy, capecitabine has the best economic profile of all alternative regimens. Drug acquisition costs are by far the most important factor driving costs in all regimens.