INTRODUCTION Based on the results of several randomised controlled trials, epidermal growth factor receptor (EGFR) tyrosine kinase inhibitors (TKIs) have now replaced platinum-based chemotherapy as first-line therapy for advanced non-small cell lung cancer (NSCLC) harboring an activating EGFR mutation. Areas covered: This review describes the EGFR pathway and its abnormalities in NSCLC and discusses the differential molecular and clinical activity of first and next-generation EGFR TKIs in the first-line treatment of tumors with an activating EGFR mutation, with a special focus on the second-generation agent afatinib. A comprehensive literature search was conducted to identify all relevant clinical trials including abstracts from most recent meetings to provide up-to-date information on this topic. Expert commentary: While the first-generation EGFR TKIs erlotinib and gefitinib exhibited good tolerability and improved progression-free survival compared with a platinum doublet, they failed to improve overall survival (OS). In contrast, clinical trials of afatinib (LUX-Lung 3 and 6) demonstrated a significant OS advantage over a platinum doublet, particularly in patients whose tumors harbored the Del19 mutation. Moreover, in a head-to-head comparison afatinib improved efficacy versus gefitinib in patients with common EGFR mutations across a range of clinically relevant endpoints. Afatinib is therefore a promising first-line option in these patients.