Serum adiponectin concentrations are negatively correlated with body fat percentage and with the risk of colorectal cancer. However, few studies have examined the relationship between adiponectin receptor expression and colorectal cancer. We measured the expression levels of the AdipoR1 and AdipoR2 genes by quantitative real-time reverse-transcription polymerase chain reaction in 202 paired specimens of cancer tissue and adjacent normal mucosa obtained from patients with colorectal cancer. To evaluate the clinical significance of AdipoR1 and AdipoR2, correlations between the expression of these genes and clinicopathological features were examined. Both genes were expressed in colorectal cancer and in adjacent normal mucosa. The expression levels of the genes were significantly higher in cancer tissue than in normal mucosa (P<0.0001). Reduced expression of the AdipoR1 gene was correlated with venous invasion, but not with any other clinicopathological feature examined. Our findings suggest that reduced expression of the AdipoR1 gene may be a useful predictor of venous invasion.