Semiconductor quantum dots (QDs) are nanocrystals that possess unique optical features due to their quantum confinement effect. Among these properties size-tunable and narrow emission wavelengths, simultaneous excitation of multiple colors, broad absorption profiles and high photostability can be listed. QDs surface can be functionalized by conjugation with biomolecules enabling the nanoparticles to be dispersed in water and to be specifically addressed for biomedical and biopharmaceutical applications. Here, we present physicochemical characteristics of QDs, and the recent data on the perspective of QDs application as the new generation of nanoparticle-mediated drug delivery systems (NMDD) as well as on their cytotoxicity.