A 76-year-old man with renal dysfunction received FOLFIRI due to a relapse in his pelvis after surgery for sigmoid colon cancer. FOLFIRI was continued for approximately 21 months with stabilization of disease observed on CT scans, but his tumor marker levels increased and tumors showed progression. He then began treatment with cetuximab/CPT-11, but disease progression was observed. XELOX in a low-dose was then administered, but this therapy was discontinued because of progression. He could not receive the other antitumor agents, due to mutations of the KRAS gene and renal dysfunction. Therefore, FOLFIRI was restarted, because it can be continued for long periods of time. Consequently, his tumor marker levels decreased with stabilization of disease on CT scans, and he continued the therapy for 7 months while maintaining quality of life. Ultimately, this case suggested that if there was effectiveness from a previous treatment, retreatment would be successful as chemotherapy for colon cancer in the difficult situation of selecting the other effective antitumor agents.