The role of EGFR in cancer development and progression has been recognized for long time in a variety of human malignancies including lung, head and neck, colon, breast, ovary and glioma. Recently its role as a target of antineoplastic agents has also been identified and a variety of EGFR-targeted drugs is already being used in a clinical setting and others are at present under investigation. Many data involving EGFR protein expression are now available for the choice of anti-EGFR monoclonal antibodies in colorectal cancer and with regard to EGFR gene mutations for the choice of tyrosine kinase inhibitors in lung cancer. Other EGFR-related molecular factors, including the EGFR gene copy number, are currently under investigation. This review summarizes both preclinical and clinical available data regarding EGFR genomic alterations as prognostic and predictive factors.