Natural rubber is the oldest elastomer in use. Its consumption is still growing, and currently about 42% of the elastomers globally used is natural rubber. However, the compatibility of new rubber additives, e.g. silica, can pose a problem; therefore modified natural rubber types were introduced. The properties and advantages of modified natural rubber grades will be addressed in this lecture, as well as their availability. Compounding principles and applications of the different natural rubber grades will be discussed.