Predictive medicine represents a new philosophy in healthcare involving the detection of pathology-specific molecular patterns before the emergence of signs and symptoms, which in some diseases (e.g., diabetes) surged accompanied by severe secondary complications. Advanced drug delivery systems (DDS) present important benefits for this new and fascinating area, since they enable to deploy active molecules in specific targeted regions of the body in a controlled manner. The exponential development achieved in DDS during the last decades can be used to develop effective solutions for the premature detection and effective treatment of different pathologies. Polymers provide the ideal opportunities for the development of new effective DDS due to the easy processing and to the control over the physical and chemical characteristics that can be accomplished during the polymerization. This chapter provides an overview of the available DDS in view to understand the most important concepts of the area. An important focus is given to the sort of polymers commonly used and reported in the literature, while the advantages and disadvantages of each type of material is critically discussed. Finally, the miniaturization of DDS is described and the most important methods to prepare micro- and nanocarriers are presented.