Abstract Purpose: To evaluate the impact of KRAS mutation type as a predictor of response to different chemotherapy regimens (oxaliplatin-based, Irinotecan-based). Methods: This is a retrospective study included 198 patients with metastatic colorectal cancer (mCRC) diagnosed and managed at medical oncology department, clinical oncology department, pathology department, oncology department in Health Insurance hospital, data regarding clinic-pathological features of the disease, pattern of KRAS mutation and response to chemotherapy is retrospectively collected and analyzed. Results: KRAS codon 12 mutations were more common in males while codon 13 mutation that was more common in female patients (P<0.05). Right-sided colon experienced a significantly increased number of KRAS codon 13 mutations, while codon 12 was more in the left side (P<0.05). There was no difference between both treatment arms regard Progression-free survival (PFS), in wild type also there was no difference, but PFS in patients with codon 12 mutation receiving oxaliplatin protocol was statistically significantly higher than patients with codon 13 mutation (P 0.016). In patients with codon 13 KRAS mutation PFS was statistically significantly higher in Irinotecan arm than in oxaliplatin arm (P 0.001). Conclusion: we can tailor chemotherapy according to the type of mutation as patients with codon 12 mutation gets more benefit with first line oxaliplatin containing protocol, while those with codon 13 mutation gets more benefit of Irinotecan based protocol. Keywords: mCRC, KRAS, Oxaliplatin, Irinotecan.