Polyurethane (PU) has become one of the most widely used plastics for various applications such as thermal insulation, automotive parts and seating materials. Polyols for PU production are derived mostly from petrochemical products but can be replaced by renewable materials. The use of renewable resources in materials has attracted great interest in both industrial and academic fields because of their environmental aspect and sustainability [1]. Nanocellulose is often being regarded as the next generation renewable reinforcement for the production of high performance bcomposites. Cellulose nanowhiskers have been widely investigated as reinforcement in PUs. Therefore cellulose nanorystals could be candidate for reinforcing PU composites [1-2]. In this research, the cellulose nanocrystals (CNC) were successfully obtained from microcrystalline cellulose and dispersed in a PU matrix. PU matrix was prepared from hydroxylated soybean oil Agrol (OH=120.8 mg KOH/g), tertiary amine catalyst and polymeric diphenyl diisocyanate. Nanocomposites containing 0.5, 1.0 and 2.0 wt% CNC were prepared. Thermal properties and tensile strength of the resulting films were evaluated. Also, dynamic mechanical analysis (DMA), Fourier transform infra-red tests and X-ray diffraction tests were carried out.