Hevea brasiliensis tree is the only source of natural rubber (NR), and for decades, has had a significant share (more than 40%) in the elastomeric market. This biopolymer is made of poly(cis-1,4-isoprene) associated with several other biological compounds. In this chapter, first, the current challenges faced by the NR supply chain are reviewed. Then the latest information available on poly(cis-1,4-isoprene) biosynthesis pathway as well as a review of the nonisoprene content, which gives its specific properties, is presented. Since the chemical and spatial arrangements are highly important for an understanding of the properties of NR, different structural levels of NR are also described. Finally, two industrial applications of NR, antivibratory parts and tires, are reported.