Since the first cancer chemotherapy use, efforts have been made in identifying drugs with an antitumor specific action, but cancer is a very complex situation to be cured with a single agent, and to increase drugs selective cytotoxicity new agent combinations, or innovative cellular cycle related schedule, or the use of pro-drugs have been developed. Notwithstanding some relevant improvements in results, chemotherapy remains often a palliative approach. The improved knowledge of the biology of cancer, and of molecular mechanisms and specific targets, has recently modified the approach to various tumors. In particular, the identification of a single and specific genetic alteration in some tumors such as myeloid chronic leukaemia or gastrointestinal stromal tumors (GIST) led to the development of imatinib, a "target" drug with a multikinase inhibitor activity towards the specific genetic alteration; this unique opportunity is not applicable to other tumors, because usually tumors have multiple genetic alterations with very complex molecular pathways. The development of drugs with a multitarget action is probably the best approach to the majority of human cancers, but other possibility are the combination of multiple agents, each with known selective activity towards a specific molecular target, or the choice of a chemotherapic drug in combination with one or more molecularly targeted drugs. The knowledge of the multiple and extremely complex molecular pathways of the neoplastic cells will hopefully drive oncologic science towards a more "exact" science, with the use of "personalized" treatment in each cancer patient.