Interleukin-18(IL-18) is a cytokine with many functions. This study was to investigate the serum levels of IL-18 and their clinical significance in patients with colore3ctaql carcinomas. Methods: Peripheral blood samples were obtained from 106 patients with colorectal carcinoma and 60 volunteers. The serum IL-18 levels were determined in each sample with an enzyme-linked immunosorbent assay (ELISA). Results: In patients before 1997, the mean IL-18 level was 338.46 pg/ml; in patients after 1997, the mean IL-18 level was 328.85 pg/ml, there is no evidence of loss of IL-18 immunoreactivity after prolonged storage at -80℃. The mean serum IL-18 level in 106 patients with colorectal carcinoma was significantly higher compared with the 60 healthy volunteers (P<0.05). Although the IL-18 level in patients with stage I did not differ from controls, the serum IL-18 levels of patients with stage II, stage III and stage IV disease were significantly higher compared with healthy control (P<0.05). The mean serum IL-18 level of patients with stage III disease, while the difference between patients with stage II and stage IV was not statistically significant (P>0.05). The survival rate of patients with IL-18 levels ≥346 pg/ml (n=47 patients) was significantly worse compared with patients who had IL-18 levels <346 pg/ml(n=57 patients). The 5-year-survival rates were 5.3% and 18.6%, respectively. Multivariate analysis using a Cox proportional hazards model identified the serum IL-18 level as an independent prognostic factor for survival Conclusion: The serum IL-18 level has a significant correlation with survival curve. The serum IL-18 level may represent a significant postoperative prognostic determinant in patients with colorectal carcinoma. This study was to investigate the serum levels of IL-18 and their clinical significance in patients with colore3ctaql carcinomas. Methods: Peripheral blood samples were obtained from 106 patients with colorectal carcinoma and 60 volunteers. The serum IL-18 levels were determined in each sample with an enzyme-linked immunosorbent assay (ELISA). Results: In patients before 1997, the mean IL-18 level was 338.46 pg / ml; the mean IL-18 level was 328.85 pg / ml, there is no evidence of loss of IL-18 immunoreactivity after prolonged storage at -80 ° C. The mean serum IL-18 level in 106 patients with colorectal carcinoma was significantly higher than the Sixty-one healthy volunteers (P <0.05). Although the IL-18 level in patients with stage I did not differ from controls, the serum IL-18 levels of patients with stage II, stage III and stage IV disease were significantly higher compared with healthy control (P <0.05). The mean serum IL-18 level of patients with stage III disease, while the difference between patients with stage II and stage IV was not significant significant (P> 0.05). The survival rate of patients with IL-18 levels> 346 pg / ml (n = 47 patients) was significantly worse than with patients who had IL-18 levels <346 pg / ml (n = 57 patients). The 5-year survival rates were 5.3% and 18.6%, respectively. Multivariate analysis using a The serum IL-18 level may represent a significant postoperative prognostic determinant in patients with colorectal carcinoma