In this study, cuprous oxide nano particle (Cu2O) was used as a modifier in asphalt binder to investigate the fatigue and rutting performance of asphalt binder and moisture susceptibility of Hot Mix Asphalt (HMA). The objective of the study is to determine optimum modification percentage to improve the low and high temperature characteristics of asphalt binder. Base asphalt binder was modified by cuprous oxide nano particle in three percentages (1.5%, 3% and 4.5%). High and low temperature characteristics were determined by Dynamic Shear Rheometer (DSR) and Bending Beam Rheometer (BBR). Rheological properties were also determined by softening point, ductility, elastic recovery, viscosity, and penetration of modified samples and compared to base asphalt binder. Optimum cuprous oxide nano particle percentage was recommended as 1.5%. As a result, 1.5% cuprous oxide nano particle was determined the best content of both rheological properties and strength. (C) 2019 Elsevier Ltd. All rights reserved.