Objective: Colorectal cancer is one of the most common forms of cancer in the world. Among Several genetic events that have been documented in colorectal tumour progression,K-ras has high diagnostic value .studies have shown that K-ras mutations are found in 20-50% 0f all colon cancer mostly in codons 12 and 13, and less frequently in codon 61.The aim of this study is to identify K-ras gene mutations in codon 13 in Iranian CRC patients and to assess whether they are linked with the clinicopathological parameters. Materials and Methods: Tumor samples were collected from a consecutive series of 54 patients undergoing resective surgery for CRC. DNA was extracted from tumour. We applied RFLP-PCR for codon 13 mutation detection. Results: Colorectal patients, 18.5%, presented with mutations in codon 13 of K-ras. In our study K-ras mutations were significantly associated with CRC stage and age (p>0.05). No significant correlations were found between the mutations and sex, ,grade and tumor location. Conclusion: According to significant correlation between age and tumor stage with mutation in codon 13 of K-ras ,we expect younger patients with colon cancer and lower response rate to treatment and higher stage in our country.