Bitumen prices have increased dramatically due to rising oil prices and increased traffic volumes around the world. This situation has caused the use of bitumen with higher viscosity, low-cost bitumen for pavement construction and the development of alternative materials that have a good rheological effect and have less negative impact on human health and the environment. The application of fibers in asphalt mixtures has been studied for the past few decades to improve pavement performance worldwide. This study was carried out on three types of bitumen modified with two types of fibers: brown recycled wool fibers (BRWF), which are locally available in the country, and polyester fibers (CPF), which are considered as waste. It was used to produce bitumen modified with fibers. The physical and rheological properties of modified bitumen were evaluated using traditional physical tests (penetration, softening point, and rotational viscosity tests) as well as dynamic shear rheometer (DSR) test. Compared to the original bitumen, the fiber reinforced bitumen had higher softening point, viscosity and composite modulus, but their penetration decreased. The results of the tests showed that the use of both types of fibers as modifiers for bitumen improves their performance at high temperature by increasing a performance grade (PG). Increasing bitumen stiffness is expected to increase pavement rutting resistance. Consequently, these fibers can be used as additives for bitumen and asphalt mixtures to increase their performance.