Curing characteristics, tensile properties, fatigue life, swelling behavior, and morphology of waste tire dust (WTD)/carbon black (CB) hybrid filler filled natural rubber (NR) compounds were studied. The WTD/CB hybrid filler filled NR compounds were compounded at 30 phr hybrid filler loading with increasing partial replacement of CB at 0, 10, 15, 20, and 30 phr. The curing characteristics such as scorch time, t(2) and cure time, t(90) decreased and increased with increment of CB loading in hybrid filler (30 phr content), respectively. Whereas maximum torque (M(HR)) and minimum torque (M(L)) increased with increasing CB loading. The tensile properties such as tensile strength, elongation at break, and tensile modulus of WTD/CB hybrid filler filled NR compounds showed steady increment as CB loading increased. The fatigue test showed that fatigue life increased with increment of CB loading. Rubber-filler interaction, Q(f)/Q(g) indicated that the NR compounds with the highest CB loading exhibited the highest rubber-filler interactions. Scanning electron microscopy (SEM) micrographs of tensile and fatigue fractured surfaces and rubber-filler interaction study supported the observed result on tensile properties and fatigue life. (C) 2011 Wiley Periodicals, Inc. J Appl Polym Sci 121: 1143-1150, 2011