Polymeric micelles have recently emerged as a novel promising colloidal carrier for the targeting of poorly water soluble and amphiphilic drugs. Polymeric micelles are considerably more stable than surfactant micelles and can solubilize substantial amounts of hydrophobic compounds in their inner core. Due to their hydrophilic shell and small size they sometimes exhibit prolonged circulation times in vivo and can accumulate in tumoral tissues. This review examines the chemical nature of polymeric micelles as well as the methods used to characterize them with regard to drug delivery. Special emphasis is put on the determination of critical micelle concentration and on drug loading procedures. Potential medical applications, especially in cancer chemotherapy, are described and discussed.