The epidermal growth factor receptor (EGFR) mutation is the first recognized molecular target in non-small cell lung cancer that makes personalized therapy feasible. This molecular alteration has been demonstrated to be more frequent in Asians, non-smokers and patients with adenocarcinoma histology. Several retrospective and subgroup analyses of phase III trials have shown the single agent, erlotinib, to be associated with higher response rates and longer progression-free survival in patients harbouring an EGFR mutation. Two prospective randomized phase III studies from China and Europe have confirmed the role of first-line erlotinib in patients with the mutations. Erlotinib has also been evaluated in combination with chemotherapy in either a concurrent or intercalated regimen. Earlier trials were limited by little information on the EGFR mutational status of the enrolled patients, and an ongoing phase III trial with translational biomarker analysis will provide more comprehensive data on the combination.