In our work we have studied the value of the determination of serum CEA in patients with colorectal cancer. We have studied 56 patients with colorectal cancer aged 40 +/- 16 years of both sexes, 26 of whom have metastasis and 30 not. The positivity of serum CEA in the patients with colorectal cancer was 66% (37/56) in the patients without metastasis 53% (16/30) and in the patients with metastasis 80.7%. (21/26). The referent values of serum CEA were significantly lower than the values of serum CEA in the patients with colorectal cancer with and without metastasis (p1 < 0.001). Also we noticed that the values of serum CEA of the patients with colorectal cancer with metastasis were considerably higher than those without metastasis (p2 < 0.001). Analysing the values of serum CEA in the patients with colorectal cancer we noticed that all the patients of our work that had serum CEA value 20 ng/ml had metastasis. Relying on our data we conclude that the determination of serum CEA in the patients with colorectal cancer is very useful for the diagnosis and the prognosis of these patients.