OBJECTIVE: To examine the association between long-term oral low-dose aspirin and overall survival in colorectal cancer patients after diagnosis. METHODS: The literature databases, such as PubMed, Embase, Cochrane Library, Web of Science, CBM, CNKI, and Wanfang database, were extensively searched to retrieve the comparative studies about the association between low-dose aspirin use after colorectal cancer diagnosis and overall survival published before June 2014. The state 12.0 version software was used for meta-analysis. The quality of these studies was assessed using the Newcastle-Ottawa scale. RESULTS: There were eight studies meeting the inclusion criteria for meta-analysis. The total sample size of these studies included 28 103 cases and the score of all the studies was more than 6 points. Meta-analysis of the data using I(2) test showed significant heterogeneity (I(2)=78.2%, P<0.01), therefore, a random effect model was performed. Aspirin use after diagnosis was associated with longer overall survival (HR=0.732, 95% CI:0.613-0.875, P<0.01). There were seven studies with the same design or tumor stage in I-IIII period respectively for sensitivity analysis. The results of studies showed that the sensitivity was low and accurate (HR=0.687, 95% CI: 0.557-0.849, P<0.01; HR=0.682, 95% CI: 0.539-0.864, P<0.01). CONCLUSION: Meta-analysis shows that long-term oral low-dose aspirin after diagnosis of colorectal cancer is identified as a significant prognostic factor.