Aim: Little is known about molecular biology of brain metastasis (BM) from colorectal cancer and its concordance with matched primary tumors. Materials & methods: We identified 56 consecutive colorectal cancer patients who underwent neurosurgical resection of BM. Tumor samples were tested for KRAS, NRAS, BRAF and PIK3CA. The molecular profile of the brain lesion was compared with the corresponding primary tumor. Results: The molecular profile concordance rate was 95.1%. Median survival after neurosurgery was 5.5 months (95% CI: 4.7-6.3); median overall survival was 24.0 months (95% CI: 15.6-32.4). Conclusion: In this cohort, we report a high frequency of KRAS mutations and a very high concordance rate between the molecular status of BM and that of matched primary tumors.