The purpose of this study was to investigate whether whole-liver radiotherapy plus a tumor-boost dose withconcurrent chemotherapy is beneficial for colorectal cancer patients with massive and multiple liver metastases.From January 2007 to December 2012, 19 patients who exhibited massive (with a longest diameter > 5 cm) andinvasive liver metastases and multiple metastases were treated with radiotherapy and concurrent chemotherapy.The total radiation dose was 53.4 Gy (range 38.8 Gy-66.3 Gy). All of the patients received a continuous intravenousdose of 5 fluorouracil (5-FU) 225 mg/m2 concurrently with radiation. The median survival time was 19 months.The 1- and 2- year overall survival rates were 78.3% and 14.3%, respectively. Of all of the patients who presentedwith abdominal pain, 100% experienced a decrease in pain. Decreases in the rates of ascites and jaundice wereconfirmed by ultrasound and bilirubin levels. No cases of Grade 4 or 5 acute or late toxicity were recorded.There were only two cases of Grade 3 toxicity (elevated bilirubin). These data provide evidence that whole-liverradiotherapy plus a tumor-boost dose with concurrent chemotherapy is beneficial for colorectal cancer patientswith massive and multiple liver metastases.