This research was performed during the 2017 and 2018 seasons in a private orchard located at Dakahlia governorate to investigate the impact of soil potassium fertilization and foliar spray with Potassium Nano chitosan on growth, yield and berry quality of ‘Flame seedless' grapes. Results showed that foliar treatments carried out with chitosan significantly increased vegetative growth (shoot diameter and leaf area). The application of foliar Nano chitosan Potassium fertilizer significantly increased yield and berries quality. In addition, the Foliar application of Potassium Nano chitosan along with potassium sulfate treatments significantly increased N and K content in petiole of grape leaves than the control.