Hepatitis C virus (HCV) infection is one of the most common blood-borne infections worldwide. Little is known with respect to changes in HCV status during chemotherapy for colorectal cancer (CRC), and the influence of HCV infection on chemotherapy remains unclear. Between 2001 and 2012, 3,260 patients were diagnosed with CRC in our institute. We studied 77 patients who were positive for anti-HCV antibodies. We retrospectively reviewed changes in HCV load and chemotherapy toxicities. Twenty-four of 77 HCV-infected patients with CRC received chemotherapy. Their median age was 66 years, and four patients had liver cirrhosis. The remaining 20 patients were diagnosed with chronic hepatitis, and their liver function tests and blood cell counts at baseline were normal. Serum HCV ribonucleic acid level before and after chemotherapy was evaluated in ten patients, with medians of 4.0 and 3.05 log IU/ml at baseline before and after chemotherapy, respectively. Two patients demonstrated elevated transaminase levels during chemotherapy. Among the 24 HCV patients received chemotherapy, no patients suffered from febrile neutropenia or treatment delay; two required chemotherapy dose reduction. Our results indicated that chemotherapy for CRC patients with HCV infection can be performed safely without changing the viral load.