AIM OF THE STUDY: To research organs at risk toxicity for concomitant chemoradiotherapy in non-small cell lung cancer patients, research dosimetric trends for organs at risk, and present the results as a trend over the years. To research the development of acute toxicities and compare the results with the worldwide literature. SUBJECTS AND METHODS: This is a retrospective study conducted at the Oncology and Radiotherapy Clinic of the Clinical Hospital Center Split. Data were collected from patients with locally advanced non-small cell lung cancer treated with three-dimensional conformal chemoradiotherapy from 2011 to early 2019. Data were collected from patients who were treated with primary, adjuvant, and/or neoadjuvant radiotherapy. The patients involved received at least one cycle of chemotherapy. The target volumes and organs of risk were delineated according to radiotherapy guidelines. RESULTS: The median dose on PTV was 56 Gy. The most common acute toxicity was hematological toxicity (leukopenia and neutropenia) and acute radiation esophagitis. No cases of acute radiation pneumonitis were noted. No correlation has been noted between dose override on organs of risk volumes and toxicity, and we have pointed to a trend of improving dosimetric results through the years. CONCLUSION: The toxicity of treatment with 3D conformal radiotherapy for locally advanced lung cancer at the Oncology and Radiotherapy Clinic of the Clinical Hospital Center Split is comparable to the published results of other worldwide institutions. The median dose for the planned volume is slightly lower than recommended by the professional guidelines, which is reflecting real clinical practice and retrospective research.