The prognosis for patients with lung cancer is poor with an average of 5-year overall survival rate of only 10-15 % taking all clinical stages together. The aim of this study was to elucidate the impact of the radiotherapy regimen on survival. Clinical data were collected from all the Swedish Oncology Departments for 1,287 patients with a diagnosed non-small cell lung cancer (NSCLC) subjected to curatively intended irradiation (≥50 Gy) during the years 1990 to 2000. The included patients were identified based on a manual search of all medical and radiation charts at the oncology departments from which the individual patient data were collected. Patients who did not have a histopathological diagnosis date and/or death date/last follow-up date as well as patients being surgically treated were excluded from the study (n = 592). Thus, 695 patients were included in the present study. Patients who received hyperfractionated radiotherapy (HR) had a higher local control rate compared with patients receiving conventional fractionation (CF) (38 vs. 49 % local relapse). The difference in survival between the two radiotherapy regimens was statistically significant in a univariate Cox analysis (p = 0.023) in favor of HR. This significance was, however, not retained in a multivariate Cox analysis (p = 0.56). Thus, the possible beneficial effects of hyperfractionation are still unclear and need to be further investigated in well-controlled prospective clinical trials, preferably including systemic treatment with novel drugs.