Background: Currently, glycans, which are known as functional molecules in the biological system, are being under study as potential cancer markers. This study aimed to determine the level of serum L-fucose and sialic acid as the biomarkers in patients with colorectal cancer (CRC). Materials and Methods: The patients with CRC (n=40, 20 men and 20 women) participated in the present study. The spectrophotometric method was used to measure the levels of L-fucose and sialic acid in the serum of the patients. SPSS (version 21) was used to analyze the obtained data. The results were expressed as mean ± SD. Results: The mean ± SD L-fucose level in patients with CRC was 27.46 ± 4.8 ng/mL, which was more than this level in the healthy control group (18.64±3.1 ng/mL). Also, the mean ± SD serum concentration of sialic acid in patients with CRC was 2.1 ± 0.41 ng/mL, which was more than the mean ± SD sialic acid level of 1.23±0.21 ng/mL in the healthy controls. Conclusion: Serum concentration of L-fucose and sialic acid increased significantly (P < 0.05) in patients with CRC compared with the healthy controls. We believe that determining serum L-fucose and sialic acid levels could be useful for the detection of CRC patients in the early stage.