Potassium (K) is present in higher concentrations than other macronutrients in cherry fruits and is most often associated with changes in fruit quality. This study was carried out in the Sultandagi district of Afyon province between 2015 and 2017 in the cultivation "ziraat 900" sweet cherry cultivar grafted Prunus padus rootstock on aged 15-20 years. The effects of soil K applications (as potassium sulfate (K2SO4) on sweet cherry quality and mineral content were investigated. Different concentrations of K2SO4 (0, 500, 1000, and 1500 g trees(-1)) were applied under the canopy at one time before full bloom. After harvested fruit length, fruit weight, flesh firmness, water-soluble dry matter (WDM), and mineral content [Calcium (Ca), Magnesium (Mg), Potassium (K), Phosphorus (P), Iron (Fe), Copper (Cu), Zinc (Zn), Manganese (Mn)] were determined. Fruit quality criteria (fruit length, weight, flesh firmness, and WDM content), fruit K and Cu contents values increased depending on the application of K. It was observed that fruit length increased by 9%, fruit weight by 23%, flesh firmness by 24% and WDM content by 20% due to K applications. Potassium application decreased the content of Ca and Mg. This study indicates that the application of K caused an increase in the fruit quality of the sweet cherry.