Brain-specific angiogenesis inhibitor (BAI) 1 was recently isolated as a novel p53 inducible gene. BAI1 has been suggested to play a significant role in angiostasis. We studied the expression of BAI1 in 49 colorectal cancer specimens by RT-PCR. BAI1 expression was significantly reduced in colorectal cancers as compared to the extraneoplastic tissues (X(2) test, p=0.041). BAI1 expression was inversely correlated with vascular invasion and metastasis (Fisher's exact test, p 0.045). Moreover, vascularity in the colorectal cancer was inversely correlated with BAI1 gene expression (Mann-Whitney U-test, p=0.0003). These observations suggested that BAI1 expression might inhibit angiogenesis and metastasis of colorectal cancer.