The challenge of drug delivery is the liberation of drug agents at the right time in a safe and reproducible manner, usually to a specific target site. Conventional dosage forms, such as orally administered pills and subcutaneous or intravenous injection, are the predominant routes for drug administration. However, pills and injections offer limited control over the rate of drug release into the body; usually, they are involved in an immediate release of the drug. This article is about how nanoparticles can be used as an effective drug delivery system to target the drug to a specific location or organ.