Lung cancer is the leading cause of cancer deaths worldwide. Approximately 25% of nonsmall-cell lung cancers have mutations in the EGFR gene, most of which occur in hotspot regions in exons 18, 19, 20, and 21. In-frame deletions in exon 19 (~50%) and the L858R point mutation in exon 21 (~40%) are associated with a favorable response to EGFR tyrosine kinase inhibitors. In this study, mutations of two exons of 19 and 21 in 50 lung cancer tumor samples were investigated by the sequence method. From 50 lung cancer patients, 8 (16%) patients had an L858R (c.2573T>G) mutation, 6 (12%) patients had deletion type 1a mutation, and one patient had deletion type 1b mutation. Examining the sequence of candidate genes associated with lung cancer can be very important in choosing the right treatment approach.