Hansen solubility parameters (HSP) and model oils were used to predict the affinity of each block of the TPU (thermoplastic polyurethanes) with the SARA fractions (Saturates, Aromatics, Resins, Asphaltenes) of bitumen, revealing the preferential compatibility of the bitumen with the soft block of the TPU. More specifically, aromatics are highly compatible with the soft block while resins are compatible with soft and hard blocks of the TPU. Companion SAXS analysis highlighted that the microstructure of TPU is however maintained with semicrystalline hard nanodomains dispersed in a soft matrix with its amorphous part being swollen by resins. Interfacial tension measured by drop deformation retraction method (DDR) highlighted the compatibilizing role of resins as a lower interfacial tension value was measured at high resin content. In turn, different mechanical properties of TPU-modified bitumens were obtained when changing their composition. With similar morphologies for the blends (i.e. continuous TPU phase swollen with the same ratio), a decrease in rubbery storage modulus and flowing temperature was observed as the amount of resins increases.