Asphalt mixture consists of aggregates, bitumen, mineral fillers, and void ratio. Mastic refers to a blend of bitumen and filler. Filler, as the smallest part of stone materials used in the preparation of asphalt concrete mixtures, plays a crucial role in determining their characteristics. It is utilized in asphalt to occupy voids, enhance durability, decrease permeability, and ultimately improve resistance to water infiltration. Even though filler constitutes a small fraction of stone materials, altering the filler type and quantity can significantly influence the properties of asphalt mixtures. The proportions of bitumen and filler can significantly impact the mastic's properties. Therefore, studying the filler-to-bitumen ratio's effect on mastic rheology is crucial. To analyze the influence of the mineral filler-to-effective bitumen ratio on the rheological properties of bitumen mastic, a comprehensive series of mastic samples were meticulously formulated at varying ratios of filler to effective bitumen, specifically 0, 0.4, 0.6, 0.8, 1.0, 1.2, 1.4, and 1.6 weight/weight. Importantly, results from Linear Amplitude Sweep testing show a clear trend: while fatigue life improves with added filler up to a critical point, it declines with further increases in filler content. This underscores the necessity for careful consideration of filler ratios to optimize asphalt performance.