Objective To evaluate the effects of allogeneic blood transfusion (ABT) on long-term prognosis in colorectal cancer (CRC) patients undergoing surgery. Methods PubMed, EMbase, The Cochrane Library and China Biology Medicine disc(CBMdisc) were searched for studies on the correlation between ABT and clinical outcomes of colorectal cancer patients,and relevant articles were also retrieved from references. All the searches were done from inception to March, 2014.Two reviewers independently screened the literature,extracted the data and evaluated the quality of the data.Then the meta-analysis was performed by using Stata12.0 software. Results Finally 8 studies involving 5 479 patients were included.The results of meta-analysis showed that, compared with non-transfusion group,the transfusion group had significantly increased risks of overall survival (by 21%, HR=1.21;95% CI: 1.09-1.33;P<0.001) and disease-specific survival (by 47%, HR=1.47; 95% CI: 1.17-1.84;P=0.001);whereas the risks of disease free survival,local recurrence or distant metastasis were not significantly different between the 2 groups. Conclusion ABT can increase the risks of overall survival and disease-specific survival in CRC patients undergoing surgery; therefore, it is of great clinical significance to take active perioperative blood conservation strategies to decrease ABT rate.