Quantum dots (QDs) are among the most promising items in the nanomedicine toolbox. These nanocrystal fluorophores have several potential medical applications including nanodiagnostics, imaging, targeted drug delivery, and photodynamic therapy. The diverse potential applications of QDs are attributed to their unique optical properties including broad-range excitation, size-tunable narrow emission spectra, and high photostability. The size and composition of QDs can be varied to obtain the desired emission properties a makes them amenable for simultaneous detection of multiple targets. Also, numerous surface functionalizations can be used to adapt QDs to the needed application. Recent reports have shown successful use of QDs in various medical applications. With respect to in vivo applications, caution must be exercised with QDs due to their toxic components. Development of appropriate health and safety regulations and resolution of intellectual property issues are necessary for commercialization. In light of these obstacles however, QDs appear to be too valuable to nanomedicine to dismiss, and will eventually come into routine practical use.