Fruit firmness is the major limiting factor for quality and postharvest life of mango fruit. Polyamine treatment can provide an alternative for prolonging shelf life of mango fruit by delaying fruit softening. This research aimed to investigate the benefits of exogenous putrescine treatment oncell wall-degrading enzymes of ‘Nam Dok Mai No.4’ mango. Mangoes were dipped inputrescine (PUT) at 0, 1, 2 and 4 mmol/L for 20 minutes. Afterward, mangoes were then stored at 14 °C for 9 days and transferred to 25 °C storage for another 9 days. It was found that the most effective treatment was 2 mmol/L PUT which exhibited the lowest respiration rate during storage. In addition, 2 mmol/L PUT treatment delayed pectin degradation, reduced polygalacturonase and pectin methyl esterase activities. These results suggested that 2 mmol/L PUT treatment could be effective in reducing cell wall-degrading enzyme activities of ‘Nam Dok Mai No.4’ mango after harvesting for prolonging storage life of fruit by decreasing fruit softening.