The plasticity and Mooney viscosity of Cardanol Grafted Natural Rubber (CGNR), synthesized by a solution grafting technique using a peroxide initiator, has been studied in details and compared with the one of aromatic oil plasticized natural rubber (OPNR). CGNR shows a higher plasticity and a lower Mooney Viscosity as compared to raw NR. A comparison between the CGNR and OPNR vulcanizates with respect to their technical properties, curing characteristics, thermal stability and flame retardancy shows significant differences between the two. For instance, the tensile properties, thermal stability, flame retardancy and ageing properties are found to be much superior for CGNR as compared to OPNR vulcanizates.