Sulfated polysacchar ides (SPs) are a complex group of biomolecules, many of which present relevant biological activities, such as antibiotic, anti-oxidant, anti-mutant, anticoagulant, antiviral, antitumor, anti-inflammatory, immunomodu latory. Additionally, being biocompatible, biodegradable and suitable for processing into membranes, hydrogels and nanoparticulate systems, they have great potential for biomedical applications. Thus, SPs can be used for e.g., drug delivery systems, not just performing as carriers but also contributing to the bioactivity of the developed formulations. This chapter reviews the more recent research on the nanotechnological applications of SPs.