To determine the frequency and prognostic importance of pretreatment clinical characteristics in patients currently undergoing treatment for stage III non-small-cell lung cancer (NSCLC), data were collected on 378 patients receiving high-dose (120 mg/m2) cisplatin plus vinca alkaloid combination chemotherapy regimens since 1978. Variables analyzed included age, sex, weight loss, performance status, histologic subtype, presence of extrathoracic metastases, number of metastatic organ sites, presence of liver, bone, or brain involvement, prior radiation or surgery, and serum lactate dehydrogenase (LDH). The effect of a major response to chemotherapy on survival was also investigated. Using multivariable analyses, the following were found to be associated with outcome: initial performance status, with patients having a performance status of 80% to 100% having an increased major objective response rate and survival; bone metastases, which were adversely predictive of response rate and survival; elevated serum LDH and male sex, both of which were associated with shortened survival and remission duration; and the presence of two or more extrathoracic metastatic organ sites, which was associated with shorter survival. When major objective response with chemotherapy was included in a conditional multivariable analysis, it was strongly associated with longer median survival. Information from this analysis may be useful when comparing the response data of completed studies in similar patients, in designing future trials, and in the selection of cisplatin plus vinca alkaloid therapy for individual patients with advanced NSCLC.