Date palm (Phoenix Dactylifera L.) is an important agricultural commodity and has been cultivated extensively in the whole world especially in North Africa, the Middle East, as well as some parts of Central and South America and Southern Europe. The UAE is responsible for the production of 10% of the world's date palm. Considering the date palm seeds constitute approximately 10% of the fruit, these seeds are considered a waste. The date palm seed is hard to decompose into the environment, therefore the waste of it is considered a burden to the environment. Fatigue and rutting behaviors of asphalt have been always a concern for researchers in pavement technology. The modification of asphalt binder is done to produce a better performing binder. However, the increasing demand for petroleum by-products raises a concern for producing alternatives to the asphalt binder produced from petroleum. The bio-oil was suggested as an alternative as a partial replacement for asphalt binder. The bio-oil was extracted using the Soxhlet method. The effect of the addition of bio-oil derived from date seeds on the performance of asphalt binders with various oil contents was evaluated. Asphalt mastic was prepared using six-volume ratios of 0.0%, 1.5%, 2.5%, 3.5%, 4.5% and 5.5% of date seed oil (DSO) and one asphalt binder with penetration grade of 60/70 (PG 64–16). The findings of this research study showed that the addition of the bio-oil to the asphalt binder increases the penetration however, both softening point and viscosity were decreased with the addition of bio-oil. On the other hand, the rutting parameter (G*/sin δ) was dropped with the increase of bio-oil and temperature, therefore, the high-temperature performance grade (PG) of the modified asphalt binder dropped down when the 2.5% DSO was added. The Bending Beam Rheometer (BBR) results showed that the addition of bio-oil enhanced the lowtemperature performance and binders were able to tolerate lower temperatures than the unmodified binder. Rutting and fatigue