Abstract: Objective To establish the methodology for efficient screening of colorectal cancer (CRC) via detection of stool DNA methylation of X-linked apoptosis inhibitory factor (XAF) 1 gene promoter.Methods Stool specimens were obtained from patients who underwent enteroscopy followed by allocation to normal control group (n=45),colorectal adenoma group (n=30) and colorectal adenocarcinoma group (n=24),based on enteroscopic and pathological diagnosis.The methylation-specific PCR (MSP) technique was employed to detect methylation in promoter region of XAF1 gene extracted from stool DNA.Results Human geneome DNA was obtained from all the extracted DNA specimens.Methylation,based on MSP technique,was up-regulated in 15 cases of normal controls (positive rate:33.3%) and 18 cases of colorectal adenoma (positive rate:60.0%)(P<0.05) and 15 cases of colorectal adenocarcinoma (positive rate:62.5%)(P<0.05 as compared with normal controls).However,the difference between patients with colorectal adenocarcinoma and adenoma was not significant (P>0.05).Conclusions The QIAamp DNA Stool Mini Kit provides efficient and stable purification of human DNA from stool samples.Detection of stool DNA methylation status of XAF1 gene promoter may provide high sensitivity and specificity in screening colorectal neoplasms,but fruther study is still needed to verify.