Non-small-cell lung cancer (NSCLC) is a common and frequently incurable disease. Patients with advanced Stage IIIB and Stage IV disease, although not candidates for curative resection, can benefit from receiving treatment (chemotherapy and radiation therapy) that prolongs survival, alleviates symptoms, and/or reduces complications. However, these therapies are often associated with significant adverse events. Treatments have recently been developed to selectively target cancer-specific molecules and signaling pathways. By acting preferentially on tumor cells, these drugs leave normal cells relatively undisturbed, thereby limiting toxic effects and preserving the patient's quality of life. ZD1839 is one of a new class of targeted anticancer agents known as tyrosine kinase inhibitors that has demonstrated activity in the treatment of NSCLC. In clinical trials, ZD1839 produced responses in patients with relapsed or refractory NSCLC, reduced disease-related symptoms, and was associated with an improvement in quality of life. Results from pivotal trials with single-agent ZD1839 are reviewed in this article, with an emphasis on its effects on quality of life and symptom improvement.