Extending on recent progress in control of matter at the nanoscale, functional nanoparticles and drug nanocarriers are being actively developed with the promise of improved delivery of therapeutic agents. Nanotechnology-enabled drug delivery approaches usually aim at reducing the systemic distribution and associated side-effects typically observed with conventional chemotherapeutic molecules as well as increasing the therapeutic index of the active agents. The enhanced permeation and retention effect has been exploited with notable success to passively deliver nanostructured drug carriers and therapeutic nanoparticles in vivo. Strategies aimed at further enhancing the nanocarriers accumulation within tumor tissues are under intensive investigation and could enable, in a not too distant future, the realization of the long sought after goal of chemotherapy without - or with reduced - side-effects. In particular, immunotargeted approaches are widely predicted to offer much greater specificity towards the target cells and tissues. Advancement in molecular biology has indeed made a wealth of information available in biological processes and application of this new knowledge to nanostructured agents, has also generated unprecedented hope of novel molecular diagnostic and therapeutic strategies. Focusing on oncological applications, this review aims to discuss the recent developments in immunotargeting of functional nanoparticles and drug nanocarriers and the integration of these systems into clinically relevant therapeutic applications.