Objective To study the correlation between IL-6 and clinicopathologic features in rectal cancer. Methods  IL-6 expression was detected by immunohistochemistry and peripheral blood assay in rectal cancer tissues and pericarcinomatous tissues of 49 rectal cancer patients, and 30 healthy people for physical examination were taken as controls. Then its relationship with clinicopathologic features was analyzed. Results  IL-6 expression in the rectal cancer tissues was higher than that in the pericarcinomatous tissues. IL-6 expression had no relationship with age, gender, histological type or lymph node metastasis. However, IL-6 protein expression was correlated with clinical stage of rectal cancer. Peripheral blood IL-6 level in the rectal cancer patients was higher than that in the healthy persons before operation. Serum IL-6 level was significantly associated with clinical stage and lymph node metastasis (P < 0.05). Conclusions High-expression of IL-6 is closely associated with the development of rectal cancer. IL-6 may be a key factor of tumor metastasis.