Patients with stage IIIB and IV non-small cell lung carcinoma (NSCLC) harboring an activating mutation of the Epidermal Growth Factor Receptor (EGFR) Gene should be treated first-line with Gefitinib, an EGFR tyrosine kinase inhibitor (TKI). EGF receptor mutations are most common in adenocarcinomas, especially non-mucinous type, rare in squamous cell carcinomas and sarcomatoid carcinomas, and do not occur in neuroendocrine carcinomas. Therefore, the Pulmonary Pathology Working Group of the Austrian Society of Pathology, after intense discussions and in consensus with Oncologists and Pulmonologists, recommends a priori EGFR mutation analysis for all cases of adenocarcinoma, and for all other NSCLC upon clinical request. This will markedly reduce waiting time for those patients, which most likely will have the greatest benefit from EGFR TKI therapy.