Purpose: To investigate influence of various pretreatment prognostic factors in patients with early stage (I/II) non–small-cell lung cancer (NSCLC) treated with hyperfractionated radiation therapy alone. Patients and Methods: One hundred and sixteen patients were treated with tumor doses of 69.6 Gy, 1.2-Gy, twice-daily fractionation. There were 49 patients with Stage I and 67 patients with Stage II. Eighty patients had Karnofsky performance status (KPS) 90–100 and 95 patients had <5% weight loss. Peripheral tumors were observed in 57 patients. Squamous histology was observed in 70 patients and the majority of patients had concomitant disease (n = 72). Results: The median survival time for all patients was 29 months; 5-year survival was 29%. The median time to local progression and the distant metastasis were not achieved, whereas 5-year local progression-free and distant metastasis-free survivals were 50% and 72%, respectively. Multivariate analysis identified KPS, weight loss, location, histology, and the reason for not undergoing surgery as prognostic factors for survival. KPS, location, and histology influenced local progression-free survival, whereas only KPS and weight loss influenced distant metastasis-free survival. Conclusions: This retrospective analysis identified KPS and weight loss as the most important prognostic factors of outcome in patients with early-stage NSCLC treated with hyperfractionation radiation therapy.