Natural rubber (NR) is used in many applications; ranging from automobile through health to food industry. However, unfilled NR has poor properties. The purpose of this study was to evaluate the effects of carbon black (CB), carbonized and un carbonized plant wastes on the swelling behavior of NR. The plant wastes used were corn cob husk (CC), cocoa pod husk (CPH) and empty palm fruit bunch (EPFB). NR vulcanisates with carbon black and different organic wastes fillers were prepared by a two-roll mill. The swelling behavior was studied by immersion in toluene for 72 h. Carbon black and carbonised plant wastes filled NR vulcanisates had better swelling resistance than uncarbonised plant wastes filled NR vulcanisates.