The potential use of palm oil fatty acid additive (POFA) as a new rubber ingredient in carbon-black-filled natural rubber compounds was examined. It was found that the cure time (t90) and scorch time decrease with increasing POFA concentration. The Mooney viscosity of the rubber compounds was also decreased with increasing POFA concentration. The mechanical properties of the carbon-black-filled natural rubber compounds were enhanced by the addition of POFA, especially at a concentration of 2 phr. Results from the swelling measurement and scanning electron microscopy indicate that POFA has some effect on cross-link density and also improved filler dispersion.