Nano-technology is a recent advancement in science, defined as “Science, engineering, and technology conducted at the Nano scale” (National nanotechnology initiatives in USA). Applications of Nano-technology cover a vast range from basic material science, personal care applications, agriculture, and medicine. Nano-technology is used in field of medicine for treatment, diagnostic, monitoring, genetic engineering, and drug delivery. There are two main types of Nano Particles (NPs) used in drug delivery; organic NPs and inorganic NPs. In drug delivery, the drug-Nano- Particle (NP) conjugate should be able to deliver drugs to the target site without degradation in gastrointestinal track and without reducing drug activity. Further, it should attack to target cells without causing any adverse effects. The ultimate goal of NP drug delivery is to improve proper treatment, effectiveness, less side effects with safety and patient adherence as well as reduction in the cost.