Radiotherapy of locally advanced lung cancer often requires high doses potentially leading to pneumonitis. This study evaluated the rate of symptomatic pneumonitis and characteristics in these patients. This study included 278 patients irradiated for locally advanced lung cancer between 2016 and 2019. In patients experiencing symptomatic pneumonitis, patient and treatment characteristics were analyzed. Pneumonitis was diagnosed in 21 patients (7.6%) after a median of 9 (1-23) weeks. Ipsilateral lungs received mean doses >13 Gy in 21 (100%) and >20 Gy in 15 patients (71.4%). Seventeen patients (81.0%) received chemotherapy and/or immunotherapy, 12 (57.1%) had significant cardiovascular disease (all 21 patients had risk factors), 11 (52.4%) were heavy smokers (≥40 pack years), 7 (33.3%) were aged ≥74 years, 5 (23.8%) had chronic inflammatory disease and 4 (19.0%) had previous tumors. Overall pneumonitis rate was 7.6%. Frequent characteristics included high mean lung doses, systemic treatment, cardiovascular disease (and risk factors), heavy smoking, older age, chronic inflammatory disease and history of a previous tumor. Copyright© 2019, International Institute of Anticancer Research (Dr. George J. Delinasios), All rights reserved.