A comparative study was conducted to evaluate the diagnostic value of serum sialic acid and carcinoembryonic antigen (CEA) as tumor markers in cancer patients. The study involved 153 cancer patients (carcinoma, hematological malignancies, and sarcoma) and 50 healthy controls. Serum sialic acid was measured using a colorimetric method, while CEA was determined by enzyme immunoassay. Results showed that both markers were significantly elevated in cancer patients compared to controls. However, sialic acid demonstrated higher sensitivity in detecting cancer, particularly in carcinoma and hematological malignancies. Sialic acid levels were significantly higher in all cancer groups compared to controls, while CEA levels were only significantly elevated in hematological malignancies and sarcoma. The study found that sialic acid was more sensitive and specific than CEA in detecting cancer, especially in hematological malignancies. The findings suggest that sialic acid may be a better diagnostic marker than CEA for cancer patients. The study highlights the importance of early laboratory diagnosis in cancer management and supports the use of sialic acid as a more sensitive tumor marker. The results are consistent with previous studies, indicating that sialic acid is a promising tumor marker for cancer detection.A comparative study was conducted to evaluate the diagnostic value of serum sialic acid and carcinoembryonic antigen (CEA) as tumor markers in cancer patients. The study involved 153 cancer patients (carcinoma, hematological malignancies, and sarcoma) and 50 healthy controls. Serum sialic acid was measured using a colorimetric method, while CEA was determined by enzyme immunoassay. Results showed that both markers were significantly elevated in cancer patients compared to controls. However, sialic acid demonstrated higher sensitivity in detecting cancer, particularly in carcinoma and hematological malignancies. Sialic acid levels were significantly higher in all cancer groups compared to controls, while CEA levels were only significantly elevated in hematological malignancies and sarcoma. The study found that sialic acid was more sensitive and specific than CEA in detecting cancer, especially in hematological malignancies. The findings suggest that sialic acid may be a better diagnostic marker than CEA for cancer patients. The study highlights the importance of early laboratory diagnosis in cancer management and supports the use of sialic acid as a more sensitive tumor marker. The results are consistent with previous studies, indicating that sialic acid is a promising tumor marker for cancer detection.