Objective:To evaluate the ef icacy of autologous cytokine-induced kil er (CIK) cells transfusion combined with chemotherapy in patients suf ered from advanced colorectal cancer. Methods: Sixty untreated patients with advanced colorectal cancer were randomly divided into two groups. The 30 patients in the control group received chemotherapy with the regimen of xeloda plus oxiplatin (XELOX). The 30 patients in the trial group were treated with chemotherapy (XELOX) in combination with autologous CIK celltransfusion. T-lymphocyte subgroups were separated and measured by flow cytometry quality of life (QOL) was determined by EORTC QLQ-C30. The short-term curative ef ect was evaluated via imaging examina-tions. The patients’ median progression free survival time was estimated by Kaplan-Meier. Results:The T-lymphocyte im-mune activity was improved in patients received autologous CIK celltransfusion than those treated with chemotherapy alone. The subgroup of CD3+CD56+T lymphocyte was significantly increased (4.28 ± 0.45 vs 10.14 ± 1.02, P=0.01). Short-term ef icacy evaluation revealed that there was no significant dif erence in terms of objective response rate (ORR) between the two groups, but the disease control rate (DCR) was markedly increased (86.7%vs 56.7%, P=0.020) in the group treated by chemotherapy plus CIK cells compared to the group treated with chemotherapy alone. The progression free survival time was 8.64 months ( 95%CI 6.25-9.75 months) in control group and 10.15 months ( 95%CI 7.48-12.52 months) in trial group. Compared to patients in control group, the patients in trial group had significantly longer progression-free survival (P=0.046). The QOL assessment suggested the QOL in trial group was obviously improved than that in the control group. Compared with the control group, patients treated with autologous CIK celltransfusion scored more in the area of physical function and general health status, while the symptomatic scores in terms of pain, fatigue, nausea and vomiting and diarrhea were significantly reduced. Conclusion:Autologous CIK celltransfusion combined with chemotherapy can ef ectively enhance the immune activity of T-lymphocytes, prevent disease progression and improve the progression-free survival and QOL in patients with advanced colorectal cancer.