This trial was designed to determine the 1-year survival rate, efficacy, progression-free survival (PFS), and toxicity with gemcitabine in patients with stage IIIB (with pleural effusion) or stage IV non-small-cell lung cancer (NSCLC) with Eastern Cooperative Oncology Group (ECOG) performance status (PS) of 2. Gemcitabine 1250 mg/m2 was administered intravenously on days 1 and 8 of each 21-day cycle. Treatment consisted of 6 cycles; patients who responded with complete response or partial response received < or = 2 additional cycles. Forty-two patients were enrolled at 31 community-based centers between March and November 2002. Most patients had stage IV disease (74%). The median age was 73 years (range, 58-84 years), and 19% had received prior palliative radiation therapy. Patients received a median of 3 cycles (range, 1-8 cycles). The median survival was 4.8 months (range, < 1 to 19.2 months), and the estimated 1-year survival was 20%. Median PFS was 2.5 months (range, < 1 to 19.2 months), and PFS at 1 year was 11.1%. Thirty-one patients died of disease progression, and 1 each died of myocardial infarction, brain herniation, pneumonia, and respiratory failure. Seven patients were not evaluable for response; 4 refused or received no treatment, treatment in 2 failed (myocardial infarction and pneumonia), and 1 was lost to follow-up. Among 35 evaluable patients, there were 5 partial responses (14%), 10 with stable disease (29%), and 20 with disease progression (57%). Drug-related grade > or = 3 toxicities included neutropenia (18%), anemia (8%), and dyspnea (2.6%). These results suggest that patients with NSCLC with an ECOG PS of 2 may benefit from single-agent chemotherapy gemcitabine. General toxicity, including myelotoxicity, was relatively low. Further studies comparing single-agent chemotherapy with combination chemotherapy for patients with a PS of 2 are warranted.