Bitter pit is a physiological disorder in apple, which may happen during the end of season or during the postharvest. This phenomenon causes high economic losses for farmers and exporters as well. It is thought that calcium has a very strong relationship with bitter pit in apple, which appears as browning points due to the phenolic oxidation mainly during storage and death of cells directly below the fruit peels. The management of bitter pit depends on the enough and continues supplying Ca to cultivated apple trees before harvesting the fruits. The impacts of applied nano-Ca treatment on fruit quality of apple were more significant comparing to the conventional application of calcium chloride. These impacts included improving several quality characteristics such as total soluble solids in fruits, fruit firmness, titratable acidity, total antioxidant activity, total phenolic and anthocyanins content, as well as the contents of total sugars, starch, fiber, and calcium content. Therefore, there is an urgent need for further investigations concerning using of different nanofertilizers to avoid the problems of bitter pit in apple. Other applications of nanomaterials may support apple trees against this problem, which may open many fields in agro-nanotechnology.