Patients with advanced non-small cell lung cancer (NSCLC) have a very poor prognosis. Individualization of treatment and identification of therapeutic molecular targets may improve outcomes. Gefitinib was introduced recently among several other molecular-targeted drugs of activity in NSCLC. Gefitinib is indicated for patients diagnosed with advanced or disseminated NSCLC with an activating mutation in the EGFR (epidermal growth factor receptor) gene. The paper summarize experience with gefitinib in the Department of Lung and Thoracic Tumors of Maria Sklodowska-Curie Memorial Cancer Centre and Institute in Warsaw.