Introduction: Colorectal cancer (CRC) is a formidable health problem worldwide. It is the third most common cancer in men and the second most common in women. In India, annual incidence rates (AARs) for colon cancer and rectal cancer in men are 4.4 and 4.1 per 100000, respectively. Sialic acid and CA 242 are important tumour markers in CRC. Objective: To correlate serum CA242, and serum Sialic acid levels in pre-operative and post-operative CRC patient. Methodology: The patients attending the State Cancer Institute at IGIMS, Patna with colorectal cancer (n=15) were included in the study for a period of 6 months. Serum CA242 level by ELISA method and serum sialic acid level by Ninhydrin Method. Statistical Analysis: Paired t-test was done to compare groups and Pearson correlation coefficient was evaluated for correlation between the parameters. Results: The mean level of sialic acid pre and post operative cases was 1.76 + or - 0.15 & 1.17 + or - 0.59 respectively and for CA242 was 49.5 + or - 33.3 & 31.8 + or - 22.6 respectively. There was a significant difference between pre and post operative serum sialic acid and CA242 level (r=0.566, p=0.028) (p<0.05). Conclusion: The prognosis is found to be better after the surgical resection of CRC. Keywords: Serum CA242, Sialic acid, Colorectal cancer, Pre & Post operative