<p>Autumn Royal is a black seedless grape that is perishable and susceptible to water loss due to desiccation of the rachis and pedicel, which remarkably contributes to reducing cellular integrity. Calcium chloride (CaCl₂) is an eco-friendly compound that effectively helps in maintaining membrane coherence and reducing oxidative stress during storage. This study aimed to evaluate the effects of preharvest application of calcium chloride on the biochemical, phytochemical, and antioxidative enzyme activity of Autumn royal grapes during cold storage. For the execution of this experiment, various concentrations of CaCl₂ (control, 2%, and 3%) were applied to the grape at the berry set stage. After harvesting, grape bunches were kept at a low temperature (4 ± 1℃) with 85 ± 5% relative Humidity for 20 days. The results indicated that preharvest application of 2% CaCl₂ significantly reduced weight loss, decay incidence, and hydrogen peroxide accumulation during storage compared to control. Treated berries also exhibited a higher marketability index, along with better retention of total soluble solids, titratable acidity, and ripening index. Moreover, CaCl₂ treatment enhanced nutritional quality by maintaining elevated levels of ascorbic acid, total phenolic content, and DPPH radical scavenging activity. Additionally, CaCl₂ application significantly boosted the activity of antioxidant enzymes such as superoxide dismutase, peroxidase, and catalase, while suppressing the activities of cell wall-degrading enzymes, including cellulase, polygalacturonase, and pectin methylesterase, thereby contributing to maintained firmness and sensory attributes throughout the storage period as compared to untreated grape berries. Overall, the findings of this study suggest that preharvest application of CaCl₂ can effectively maintain the quality of grape berries cv. Autumn royal while preserving the physical attributes without compromising biochemical and sensory qualities during cold storage.</p>