Nanoscale polymeric particles, in particular self-assembled block copolymer micelles, have been utilized in pharmaceutics for development of novel therapeutic and diagnostic modalities. Advantages of the polymeric micelles include their small size, long circulation in bloodstream, ability to circumvent renal excretion and extravasation at sites of enhanced vascular permeability. They can be designed to facilitate the incorporation of a variety of compounds or even particles through a combination of electrostatic, hydrophobic, and hydrogen bonding interactions. Micelle structure can be tuned to control the drug-release characteristics of the micellar carriers. Stabilization of the micelles via covalent cross-links between polymer chains can reinforce the multimolecular assembly of the micelles and prevent their structural deterioration upon dilution, environmental challenges and shear forces. Chemical functionalization of polymeric micelles with targeting moieties was also explored in order to enhance accumulation of highly toxic ingredients specifically within cancer cells and prevent their accumulation in healthy organs. The potential application of such polymeric micelles as carriers for multidrug delivery will be discussed.