<p>‘Maha Chanok’<strong> </strong>mango is an economic fruit crop widely cultivated commercially throughout Thailand. By nature, mango fruit has a rather limited storage life after harvest. 1-methylcyclopropene (1-MCP) has been accepted as a commercial substance to improve several fruit qualities. The objective of this research was to study the effects of 1-MCP on the external postharvest qualities and storage life on the ‘Maha Chanok’ mango fruit. The experiment was laid out in a Completely Randomized Design with three replicates, ten fruits per replicate. Mango fruit was fumigated with 1-MCP at three concentrations (1000, 1250, or 1500 nl l^-1) and three fumigation periods (12, 18, or 24 h), compared with the control fruit. After treating, all treatments were stored under ambient temperature (27 °C, 80%R.H.). The following determinations were made every two days for assessment of fruit weight loss, firmness, chlorophyll content, decay incidence, and storage life. The results showed that fruit treated with 1500 nl l^-1<strong> </strong>1-MCP for 24 h had the maximal fruit firmness. For chlorophyll content, the results showed that fruit-treated with 1500 nl l^-1<strong> </strong>1-MCP for 12 h could effectively retain the highest chlorophyll contents. Furthermore, both the lowest fruit decay and the longest storage life of 12 days were achieved from the fruit treated with 1000 nl l^-1<strong> </strong>1-MCP for 12 h.</p>