Quantum dots have specific optical and electronic properties which makes their wide application in the field of nano bio technology. The emitted photon energy in a quantum dot increases with a decrease in the dot size. Since quantum dots are tunable hence by injecting quantum dot based probes multi color imaging of tumor cells, cancer cells and lymph nodes can be accomplished which is very advantageous in the medical field. Various researches have been done and much is going on where quantum dots works as an efficient drug carrier system during analysis or treatment in targeted drug delivery. Quantum dots can be applied to cell for drug screening and analysis. Linking with antibodies as biological labels makes them appropriate for various applications in cellular and molecular imaging. [Med-Science 2017; 6(3.000): 598-602]