Objective: Colorectal cancer is a common disease. Mutant pS3 gene - a gene that suppresses tumor act as "guardians" of the gene - is considered as a poor prognosis of colorectal cancer patients. Mutant p53 gene rate of medical literature was about 45 percent. The aims of this study were to determine the possible association mutant p53 gen with prognosis and postoperative outcome. Material and method: This is a cohort study of 100 patients who underwent colorectal surgery for cancer at UMC. Results: There were 50 percent of cases with p53 protein overexpression. The rate of mutant p53 gene in exon 5,6,7,8 was 50 percent. P53 gene mutation was significantly associated with the tumor differentiation, vessel invasion. Recurrence rates in the group with p53 gene mutation was 20.9 percent higher in the group without p53 gene mutation was 12.2 percent (p = 0.25). Overall survival after 20 months in the group with p53 mutation was 81.4 percent in the group without p53 gene mutation is 87.8 percent (p = 0.56). Conclusion: Mutant p53 gene was significantly associated with tumor differentiation and blood vessel invasion that are the factors for poor prognosis of colorectal cancer. There was no significant correlation between mutant p53 genes with recurrence rates and overall survival.