Composites of natural rubber were prepared with TiO2 and nanosilica. The stress relaxation behavior of the composites under tension was studied with reference to the filler loading and strain level. It was observed that the rate of stress relaxation increases with increase in filler loading. The rate of stress relaxation was found to be higher for silica-filled NR compared to TiO2-filled NR. This is due to the high degree of agglomeration in silica compared to titanium dioxide filler. The effect of ageing on the stress decay was also investigated and the rate of stress relaxation was found to decrease after ageing. The experimental curves were fitted with the stretched Kohlrausch equation. From the fitting parameters, the relaxation time and the stretching exponent were estimated in order to understand the mechanism of the relaxation processes in the filled natural rubber composites.