JS-1 is a novel gene located at 5p15.2 and originally detected in primary oesophageal cancer.  Our previous study reported frequent overexpression of JS-1 in oesophageal cancers and confirmed its tumour transforming capacity in normal cells, indicating a potential role in the molecular carcinogenesis of human cancers. The aim of this study was to determine the gene copy number JS-1 in a small cohort of patients with colorectal tumours. We evaluated the DNA copy number of JS-1 in 40 colorectal tissues (30 adenocarcinomas, 10 non-neoplastic tissues) using real-time polymerase chain reaction. JS-1 DNA was detected in all selected colorectal cancer and control tissues. Copy number for JS-1 was significantly higher in colorectal cancers compared to the non-cancer control tissues (p=0.003). Among the cancers, 97% (n=27/30) showed high JS-1 copies at the DNA level when compared to the control tissues.  This is the first study showing significant correlation of JS-1 copy number with malignancy in colorectal tissues. High gain of JS-1 copies in colorectal cancers confirms our earlier finding of the oncogenic properties of JS-1 in oesophageal cancers. To conclude, these results suggest that JS-1 is involved in the pathogenesis of colorectal cancers and future research needs to be undertaken to comprehend the role of this novel gene in molecular carcinogenesis.