Current development in the design of asphalt concrete especially in the upper layers of flexible pavements contains about acceptable proportion of mineral fillers, which contributes towards the mix cohesion, resistant to rutting and improves serviceability. It is well recognized that mineral fillers play an important role in the properties of mastics and hot-mix asphalt (HMA) mixtures. Better understanding of the effects of fillers on the properties of mastics and HMA mixtures is crucial to good mix design and high performance of HMA mixtures. This paper presents a laboratory investigation into the effects of different fillers on some properties of HMA mixtures.