The treatment of solid malignancies includes various target drugs, such as monoclonal antibodies and tyrosine kinase inhibitors, which exert their effect alone or in combination with chemotherapy. The main part of these molecules have a target on proteins of EGFR and VEGF pathways. The particular toxicity profile and the financial impact, deriving from the application of these agents in cancer treatment, prompted a lot of researches to define predictive factors of their efficacy. Various biomarker were identified among the components of the targeted pathways. However just few studies allowed to identify specific factors to predict the toxicity of these drugs. In this review EGFR and VEGF-related pathways are described, most relevant clinical findings about target therapy applications are exposed and the clinical impact of predictive factors of efficacy and toxicity are discussed.