Gray mold, caused by Botrytis cinerea, is the most important disease which causes major quality and quantity losses in preharvest period and postharvest storage of grapes. Grapes are commonly treated with sulfurdioxide (SO2) to control decay caused by Botrytis cinerea both in vineyard and during storage. However, there is need for natural alternatives to replace SO2 because of many considerations related with sulfite residues, emergence of B.cinerea resistant strains, hazards for human and environment, negative effects on quality characteristics and sustainability, and certification for organic grapes. In this study, the effects of alginate solution with or without (w/wo) vanillin as preharvest spray and postharvest edible coating on quality, safety and biochemical properties of grapes from Semillon Blanc, Alphonse Lavalleé and Razaki cultivars were investigated. Soluble solid content, pH, titratable acidity, total phenolic content, antioxidant activity, yeast-mold counts, lactic acid content, color, and firmness were determined at the day of preharvest treatment, at harvest and during 35 days of storage at 4±2°C. In addition, sensory evaluation of grapes coated w/wo vanillin were also performed using hedonic scale test. Alginate treatments w/wo vanillin were effective in preventing weight, soluble solids, acidity, and firmness losses. Incorporation of vanillin into alginate coating provided significant reduction in yeast-mold growth. Moreover, phenolic content and antioxidant activity of grapes treated with alginate coating incorporating vanillin were higher than others during postharvest storage. In sensory evaluation, appearance was ranked as the highest for alginate coating wo vanillin. As a conclusion, alginate solution enriched with vanillin could be a natural alternative of synthetic fungicides to prevent deteriorations and enhance quality of grapes.