Gemcitabine (2'-2'-difluorodeoxycytidine) is a recently developed pyrimidine antagonist that is structurally related to cytarabine (ara-C). When phosphorylated intracellularly, gemcitabine inhibits ribonucleotide reductase and arrests cell cycling in the S phase. Paclitaxel is a potent promoter and stabilizer of microtubule spindle formation and an inhibitor of cell cycling. In this report, we discuss 2 patients with advanced-stage non-small-cell lung cancer (NSCLC) treated with a combination of gemcitabine/paclitaxel who developed pulmonary symptoms of dyspnea and cough. Chest radiographs and computed tomography revealed diffuse pulmonary infiltrates. Bronchoscopic evaluation revealed diffuse alveolar damage with associated type II pneumocyte hyperplasia without evidence of infection or metastatic carcinoma, suggesting the development of a drug-induced pulmonary toxicity. Both cases improved with the discontinuation of gemcitabine/paclitaxel and with supportive care including steroids in one of the patients. We also review the published case reports of pneumonitis believed to be secondary to the taxanes or gemcitabine when used as single agents and a solitary case report describing pneumonitis in the setting of both a taxane and gemcitabine. Because the combination of gemcitabine/paclitaxel has demonstrated activity in NSCLC, the use of this combination is likely to increase. Clinicians caring for lung cancer patients receiving this combination should be aware of this potential pulmonary toxicity.