The expression of ABCG2 in colorectal cancer and its relationship with invasion and metastasis is still not clear. In our study, immunohistochemical staining of ABCG2 was therefore performed for 60 cases of primary colorectal cancer. ABCG2 positive cancer cells were found to be mainly positioned in the front of carcinomatous tissue or between carcinomatous and non-carcinomatous margin tissues. In carcinomatous tissues and non-carcinomatous margin tissues, high expression rates forABCG2 were 36.7% (22/60) and 3.3% (2/60) respectively, with significant difference (chi2=5773.3, P<0.001). The rates of high expression of ABCG2 were 30% (9/30) and 6.7% (2/30) in 30 cases with and without positive lymph nodes, respectively. (chi2=5.45, P<0.025). From the present results expression of ABCG2 may be important in the progression and metastasis of colorectal cancer.