The improvement in the performance characteristics of the asphalt binders mixed with soybean derived materials (SDM) was established in recent years. In this research, the effect of adding SDM at 5% by weight of binder to commercial asphalt binders was studied. The rheological characteristics of unmodified and SDM modified asphalt binders were evaluated using Dynamic Shear Rheometer (DSR), Bending Beam Rheometer (BBR) and Rotational Viscometer (RV) tests. The changes in the rheological characteristics of unmodified and SDM modified asphalt binders were assessed using performance grading (PG), temperature-frequency sweep and linear amplitude sweep (LAS) testing. The SDM and asphalt binders’ compatibility was checked through the storage stability tests. The Fourier Transform Infrared-Attenuated Total Reflection (FTIR-ATR) was used to study the effects of SDM mixing on the chemical compositions and ageing characteristics of asphalt binders. The testing results were analysed by Superpave, black space & Cole–Cole diagrams, master curve and the viscoelastic continuum damage (VECD) model. The results showed that the SDM modified asphalt binders improved fatigue and rutting performance parameters by 67% and 45%. FTIR-ATR results revealed a new ester carbonyl functional group of triglycerides at wavenumber 1744 cm⁻¹ in asphalt binders mixed with soybean oil.