Objectives: Carcinoembrionic Antigen (CEA) and carbohydrateantigen 19-9 (CA 19-9) are the most commonly used tumor-associated antigens in the colorectal cancer. Several contradictory studies reported that patients with meta?static colorectal cancer (mCRC) with normal serum CEA and CA 19-9 levels survived significantly longer than patients with higher serum CEA and CA19-9 levels. Methods: 240 patients with mCRC were enrolled. The parameters evaluated were age, gender, tumor location, meta?static organs, resection of the primary tumor, metastasectomy, pretreatment serum concentrations of CEA and CA19-9, first line chemotherapy regimens and overall survival (OS). CEA and CA19-9 were divided into three groups as normal (CEA ?5 ng/mL, CA 19-9 ?35 U/mL) elavated (CEA: 5–50 ng/mL, CA19-9:35–350 U/mL) and high (CEA >50 ng/mL, and CA 19-9 >350 U/mL). Primary study endpoint was overall survival (OS). Results: Serum CA 19-9 level (p=0.040), primary tumor resection (p<0.001), metastasectomy (p=0.042) and tumor lo?cation (p=0.029) were independent predictors of survival in multivariate analysis. The survival was 29.5, 21.2 and 15.4 months for the patients with normal, elevated and high CA 19-9 levels. Conclusion: High pretreatment serum CA19-9 may be a useful predictive factor of survival rather then CEA in patients with stage IV CRC.