Considerable research efforts have been directed towards developing safe and efficient natural based polysaccharide particulate drug delivery systems. The present review outlines the major new findings on the natural based polysaccharides such as chitosan, alginate, pullan, scleroglucan, guargum, gallengum and their characteristics, applications are covered. Chemically modified natural based polysaccharides or its derivatives used in drug delivery research are discussed critically to evaluate the usefulness of these systems in delivering the bioactive molecules. From a literature survey, it is realized that research activities on polysaccharide/nanocomposite systems containing various drugs for different therapeutic applications and gene therapy have increased at a rapid rate. Hence, the present review is timely worthy. It not only deals in detail about these polysaccharides but also throws on the concept of drug delivery through these polymers. We hope that the monograph will be helpful for the Medical researchers.