Interleukin-6 (IL-6) contributes to a multitude of physiological and pathophysiological processes. We sought to determine the level of the IL-6 in serum and tumoral tissue of patients with staging of the tumor and whether serum IL-6 level in patients with colorectal cancer correlate with tumoral tissue level of it. Serum and tumoral tissue specimen (stored at -80 degrees C until the biochemical determination) from colorectal cancer (n=50) were examined for IL-6.we determined the IL-6 Level in serum and tumoral tissue supernatant with Instant ELISA kit. A significant association between serum IL-6 level and staging of the tumor (P<0.001), tumoral tissue IL-6 level (r=0.95, P<0.001) in the patients was founded. IL-6 amount of the serum and tumoral tissue in the patients with colorectal cancer correlate significantly with the staging of the tumor and with each other.