To investigate whether aberration of the APC gene play any role in the development of Chinese sporadic cohwectal carcinomas, we used a polymorphic silt, located in exon 11 which created a new restriction site for Rsal to analyze LOH for the APC gene . We found that 20/29 (68.9%) patients with colorectal cancer were informative for the APC exon 11 site and loss of one allele was detected in 40% of 20 informative cases. These data suggested that loss of heterozygosity of APC gene (APC-LOH) play a role in the pathogenesis of Chinese culorectal cancer. APC-LOH is a earlier event of colorectal tumorigenesis and may be of diagnostic value in patient suffering coh, rectal cancer.