The assessment of the type and frequency of EGFR and KRAS mutations in lung cancer patients, as well as clinical-prognostic correlation, are crucial in the era of targeted therapies. EGFR-activating mutations predict responsiveness to EGFR tyrosine kinase inhibitors (TKIs) in non-small cell lung cancer (NSCLC) patients and KRAS analysis will be useful in a near future for newest target drugs. In Brazil, we have few data about the prevalence of EGFR and KRAS mutations and their knowledge would allow us to optimize personalized medicine.