Objective To systematically review the correlation between diabetes and the incidence rate of colorectal cancer, so as to provide objective proof for early screening diabetic patients with colorectal cancer. Methods The databases such as MEDLINE and EMbase published from January 1990 to July 2010 were searched to include cohort studies. The meta-analysis including seventeen qualified studies was performed by using the Cochrane Collaboration’s RevMan 4.3 software. Results The results of meta-analyses of 17 cohort studies involving 1 690 869 participants indicated that the diabetes patients had a higher incidence rate of colorectal cancer compared with the control group (16.50‰ vs. 10.13‰). The odds ratio (OR) was 1.43, and the 95% confidence interval (CI) was from 1.29 to 1.60. The results were consistent by sex compared with the control group, although the OR for colorectal cancer in diabetes was little higher in males than females (1.47 vs. 1.41). Conclusion Diabetes mellitus is a risk factor of inducing colorectal cancer.