Purpose The aim of this study was to analyze prognostic variables associated with long-term survival in patients with stage III non–small-cell lung cancer enrolled in a Spanish Lung Cancer Group (SLCG) phase II trial. Patients and Methods Between May 2001 and June 2006, 139 patients were enrolled. The initial design included 3 arms: sequential chemotherapy (CT) followed by standard thoracic radiation therapy (TRT; RT), concomitant CT/TRT followed by consolidation CT, or induction CT followed by CT/TRT. Based on the results of the Radiation Therapy Oncology Group 9410 trial, the sequential arm was closed. Induction or consolidation therapy comprised docetaxel plus gemcitabine. Concomitant treatment comprised docetaxel plus carboplatin plus 60 Gy TRT. A univariate and a Cox proportional hazard regression analysis of the following 11 variables were performed: age, sex, Eastern Cooperative Oncology Group performance status (PS), histology, forced expiratory volume in 1 second, disease stage, nodal status, hemoglobin level, completion of RT treatment, completion of induction or consolidation plus concomitant treatment, and RT delay. Results With a median follow-up of 23 months for living patients, median survival was 13.07 months for the consolidation arm and 14.65 months for the induction arm. The 4-year survival rates were 25.37% and 32.35%, respectively. Only RT treatment completion ( P < .0001) and induction or consolidation plus concomitant treatment completion ( P < .0001) were associated with longer survival. Conclusion Based on this retrospective analysis of patients enrolled in the SLCG 0008 randomized phase II study, age, sex, PS, and clinical parameters are not good predictors of overall survival; however, completion of treatment is needed to achieve long-term results.