In this study, titled "Comparative Analysis of Packaging Materials and Modified Atmospheric Packaging on the Postharvest Life of Broad Leaf Mustard (Brassica juncea var. rugosa)," conducted in HICAST, Kathmandu, Nepal, from June 13 to June 19, 2023, Investigation of the postharvest condition of 17 kg of freshly harvested broad leaf mustard. The experiment employed four distinct packaging materials—polythene, perforated polythene, muslin cloth, and MAP bags—in addition to a control group, following a Completely Randomized Design with four replications. Critical parameters such as shelf life, weight loss, moisture content, chlorophyll content, total soluble solids (TSS), pH, color, and pathological infection at 3-day intervals was monitored and evaluated. Remarkably, T2 (Polythene) and T3 (Perforated polythene) displayed a meager 3-day shelf life due to rapid decay and saturation, warranting early disposal. T5 (MAP Bag) emerged as the standout performer with a substantial average shelf life of 6 days. Moisture loss was most pronounced in the control group (T1), dropping from 96.76% to 91.2%, whereas T4 (Muslin Cloth) reached 94.82%, and T5 recorded 95.5%. MAP bags (T5) also excelled in preserving chlorophyll content and color stability. In conclusion, findings underscore the superiority of MAP bags, particularly T5, in preserving the postharvest quality and prolonging the shelf life of Brassica juncea var. rugosa, offering a promising solution for enhancing postharvest management in horticulture.