The present work deals with effect of vulcanization temperature on the polymer-filler interaction parameter, vulcanizate structure, and the technical properties of efficiently vulcanized natural rubber stocks in the presence of different fillers. We have used carbon blacks of four different particle sizes (ISAF, HAF, SRF, FT), reinforcing silica, and whiting. In the case of black fillers, as the particle size increases, reversion resistance increases. For all fillers, an increase of curing temperature from 150 to 180°C caused a reduction in strength, modulus, hardness, resilience; and an increase in elongation at break, compression set, and heat build-up. However, the flexing properties and abrasion loss showed improvement at higher curing temperature. Kraus' plots indicate that increase of curing temperature caused reduction in polymer-filler attachment. At both curing temperatures, the activity of fillers follow the order, ISAF > HAF > SRF > FT. Silica showed erratic behavior in that Kraus plots indicate nonreinforcement by the filler. Whiting also behaved abnormally with respect to Kraus plots; at lower filler loading, the system is nonadherent, becoming weakly adherent at higher concentrations. The abnormal behavior of silica-filled compounds has been explained on the basis of a reaction on the silica surface between silanol groups and zinc stearate. Westlinning and Wolff's αF values were found to be independent of curing temperature and characteristic of fillers only (the larger the particle size, the lower is the αF value). The increase in apparent crosslinking density in the case of reinforcing fillers is due to increased υr arising out of increased polymer-filler interaction. Therefore, the sulfur inefficiency parameters (E values) and zinc sulfide efficiency parameters (F values) become less significant in filled vulcanizates.