Serum CYFRA21-1 levels were studied in 127 cases of colorectal cancer. The positive rates for serum CYFRA21-1 were 34.6% in primary colorectal cancer. There was a significant correlation between the positive rates of serum CYFRA21-1 and liver metastases, peritoneal dissemination, lymph node metastases, or clinical stage. The survival rate for patients in the CYFRA21-1 positive group was lower than those with CYFRA21-1 negative group. Among patients who underwent curative operation, patients is the CYFRA21-1 positive group gave a recurrence rate of 26.6%, against 9.4% in the CYFRA21-1 negative group. There was no correlation between serum CYFRA21-1 levels and serum CEA levels. These findings suggest that Serum CYFRA21-1 levels may be a useful indicator in estimating the prognosis for colorectal cancer.