A gamma irradiation process was applied to prolong the shelf-life of grapes and changes in microbiological, physicochemical, nutritional, and sensory characteristics were investigated during 6 weeks of post-irradiation storage at $4^{circ}C$ and $25^{circ}C$. Physiochemical characteristics of grapes such as total sugar content, pH, titratable acidity, and anthocyanine content, were stable after 1 kGy of irradiation, a dose recommended by CODEX for fruits and vegetables. The viable cell counts of contaminating microorganisms were reduced 1-2 logs by this radiation dose. After 6 weeks of storage at $4^{circ}C$ the microbiological quality of irradiated grapes was stable, but all non-irradiated grapes had deteriorated. Whether or not grapes were irradiated, weight loss rapidly increased after 2 weeks of storage at $25^{circ}C$, whereas weight loss was delayed by storage at $4^{circ}C$. Immediately after gamma irradiation, the sensory evaluation results did not differ between samples, and the sensory quality of the irradiated grapes remained acceptable for over 6 weeks of storage at $4^{circ}C$. The results suggest that 1 kGy of gamma irradiation does not detrimentally affect the nutritional or physical characteristics of grapes, especially when cold storage follows radiation treatment. In conclusion, a combination of gamma irradiation and cold storage prolonged the shelf-life of grapes by 6 weeks.