Rheological effects of adding two bitumen waxes (isolated from SEC-II fraction) to three bitumens were studied using dynamic mechanical analysis (DMA). Also, a commercially available slack wax was used in the study. The results show that the magnitude and type of effect on bitumen rheology depend on the bitumen and type of crystallizing fraction in the bitumen. Effects due to wax content shown in DMA temperature sweeps are well related to the corresponding effects shown in DSC thermograms. The slope of the logarithm of the complex modulus between 25 degreesC and 60 degreesC is introduced as a possible proper factor for predicting rutting sensitivity due to wax content.