Epidermal growth factor receptor (EGFR) plays an important role in cell-cycle regulation, proliferation, differentiation, and surviving of epithelial tissues. Aberrant overexpression of EGFR can initiate uncontrolled cell proliferation with subsequent formation of epithelial carcinomas. Correlation between EGFR overexpression and increased resistance of tumor tissues to ionizing radiation has been described by many authors. Strategy of tumor radiosensitization by EGFR inhibition seems to have a great potential in the treatment of epithelial cancers. Rationale for EGFR inhibition in combination with ionizing radiaton arises from published results of many radiobiological studies, which describe the role of EGFR in cytoprotective and pro-proliferative reactions of human tumor cells, induced by irradiation. These reactions result in accelerated tumor repopulation, which is subsequently counter-productive to the effect of radiotherapy. Presented article is an overview of EGFR and its function in healthy and tumor tissues; likewise, it describes the relation of EGFR to ionizing radiation; therapeutic approaches to EGFR function modulation in combination with radiotherapy in preclinical and clinical use., Sirák Igor, Hatlová J., Petera J., Vošmík M., Ryška A., Vošmiková H., and Lit.: 147