The synergy effect of 1,6-bis(N,N`-dibenzyl thiocarbamoyl dithio)-hexane (DBTH) on the properties of filled natural rubber (NR) compounds was studied. A combined vulcanization system of sulfenamide and DBTH exhibited a significant induction time and fast cure rate. It was also found that adjusting the DBTH/sulfur ratio could easily control the cure rate and scorch time. The tensile strength and rebound properties were hardly affected by the sulfur loading in the compound. In contrast, an increase in the sulfur and DBTH concentrations produced a higher modulus and rebound and lower heat build-up. A small amount of DBTH in the compound was more effective in improving the physical properties than an excess amount. This would be related to the synergy effect between DBTH and n-tert-butyl-2-benzothiazole sulfenamide (TBBS).