Postharvest deterioration significantly affects the shelf life and marketability of mandarin fruit in Nepal. The primary causes are inadequate storage and packaging practices. This study aimed to evaluate the effects of storage conditions and plastic packaging with varying ventilation levels on the postharvest quality of mandarin fruit during storage. A laboratory experiment was conducted during January to March of 2021 to study the effect of storage conditions- room storage (15.98± 0.89 °C, 71.15± 5.80% RH), cellar storage (14.72 ± 1.20 °C, 94.28 ± 5.71% RH) and cool chamber with CoolBot (8.12 ± 0.44 °C, 79.43 ± 4.54% RH) and different plastic packaging of 25 micron: two, four, six and eight holes plastic and control (open tray). The experiment was laid out in factorial randomized complete block design with three replications. Result revealed that the lowest physiological loss in weight (9%) was recorded under CoolBot with 8 holes packaging, while the highest (23.66%) was in control under room storage. The highest total soluble solids (14.19 °brix) and the lowest titratable acid (0.88%) were observed in the control. Greater vitamin-C content was observed in CoolBot storage and 8 holes plastic packaging (27.29 mg/100g and 29.11 mg/100g respectively). The longest shelf life (91 days) was found under CoolBot storage with 8 holes plastic packaging as compared to control in room storage (32 days). Further validation across multiple seasons and commercial production settings is recommended.