KRAS belongs to the RAS family of oncogenes. KRAS mutations are detected in approximately 20% to 25% of lung adenocarcinoma. Contrary to most other oncogenic driver mutations, KRAS is more often found in smokers and is detected at lower frequency in East Asian patient cohorts. Mutations in KRAS are usually mutually exclusive with other oncogenic driver aberrations including EGFR, BRAF, HER2 mutations and ALK and ROS1 rearrangements. KRAS mutations in NSCLC most often occur in codons 12 or 13 and with a lower frequency in codon 61. KRAS Q22K mutation consists of a C to A transversion substituting lysine for glutamine. This KRAS variant, at codon 22, is exceedingly rare in lung cancers, and also only rarely been described in very few other cancers. Mutations at this site have also been reported as germline mutations in Noonan syndrome. The preclinical studies have shown that cell lines expressing the KRAS Q22K mutation possess high in vivo oncogenic potential, higher than that of wild-type KRAS. The prognostic as well as predictive role of this and other KRAS mutations continues to be studied. Although various attempts inhibiting KRAS have been made, there is no established therapy specific for this large patient subpopulation.