Microbubbles designate air or gas filled microspheres suspended in a liquid carrier phase which generally results from the introduction of air or gas. The liquid phase contains surfactants to control the surface properties as well as stability of the bubble. Microbubbles have an average size less than that of RBC’s i.e. they are capable of penetrating even into the smallest blood capillaries & releasing drugs or genes, incorporated on their surface, under the action of ultrasound. Microbubbles in general have a wide variety of applications. However in the biomedical field these are primarily used as diagnostic agents in combination with ultrasound for molecular imaging of various organs and even tumors. These are also proposed for drug and gene delivery to targeted regions in combination with various ligands. Most of the physicians today prefer imaging with ultrasound in combination with microbubbles compared to other diagnostic techniques for low cost and rapidity.