Despite improvements in conventional treatment, patients with advanced non-small-cell lung cancer (NSCLC) have a poor prognosis, leaving a significant unmet need for novel treatments. One such novel, biologically targeted agent is the orally active epidermal growth factor receptor tyrosine kinase inhibitor gefitinib. This open-label pilot trial investigated the safety, pharmacokinetics, and efficacy of 2 doses of gefitinib (250 and 500 mg per day) combined with docetaxel (75 mg/m2) in patients with locally advanced or metastatic NSCLC as first- and second-line chemotherapy. Eighteen patients were recruited: 6 received gefitinib 250 mg per day plus docetaxel; 12 received gefitinib 500 mg per day plus docetaxel. Combination therapy was feasible with no overlapping toxicities. No patients experienced dose-limiting toxicities (DLTs) at 250 mg per day; 1 patient had 2 DLT events at 500 mg per day (grade 3 rash and diarrhea for >4 days). Adverse events were mild to moderate, including fatigue, mucositis, nausea, anorexia, rash, diarrhea, and fever. Docetaxel did not appear to alter steady-state exposure to gefitinib. The effect of gefitinib on exposure to docetaxel was equivocal; with the exception of 2 patients in the gefitinib 250 mg per day dose group, there appeared to be no trend toward a higher or lower exposure to docetaxel when given in the presence of gefitinib compared with that when given alone. Combination therapy was associated with antitumor activity and responses were seen with gefitinib in 2 of 6 patients at 250 mg per day and 4 of 12 patients at 500 mg per day. This combination is feasible and has an acceptable and predictable safety profile, as well as associated antitumor activity.