We evaluated the relationship of clinical characteristics and survival in 1,635 patients with non–small cell lung cancer (NSCLC) treated in Brazil. The following variables were included: sex, age, smoking, Karnofsky’s performance status (PS), weight loss, symptoms at diagnosis (cough, dyspnea, hemoptysis, chest pain, wheezing, and hoarseness), presence of superior vena cava syndrome (SVCS), histologic type, TNM stage, and therapeutic modality (surgery, chemotherapy [CT] and radiotherapy [RT]). Multivariate prognostic models were obtained by Cox regression. Patients unsuitable for surgery or who had recidivant disease were elected to further RT and/or CT, and long-term results in this group were equivalent to those in the group treated only by surgery. A diagnosis of bronchioloalveolar carcinoma, small tumors, absence of hoarseness, treatment by surgery, and RT were independent factors related to good overall survival in stage I and II. Weight loss and clinical signs of SVCS were related to poor prognosis in stage III. PS, diagnosis of adenocarcinoma or undifferentiated carcinoma, absence of weight loss and dyspnea, N0 or N1 disease, ability to receive RT, CT, and to perform some palliative surgical procedure were good prognostic factors in stage IV. Clinical features of patients with NSCLC at diagnosis offer additional information to estimate their prognosis.