1-MCP is a new tool for regulating ethylene and preserving the quality of fresh produce. Tomato fruit Solanum lycopersicum cv. Red Ore harvested at green and pink stages was used to examine the effect of 1-MCP on their ethylene production and quality. After treating with 1-MCP for 24 hours, ethylene, ACS, ACC, CO2, color, firmness and weight loss were measured. Differences in ethylene production at mature green and pink stages, might be due to the effect of 1-MCP on ethylene production through changed activity of ACS, result in blocking of autocatalysis (mature green) and autoinhibition (pink stage). The shelf lives were improved in 1-MCP-treated fruit at both stages of harvest as indicated by the decrease in respiration, softening, and weight loss, along with the delay in color change (a-value). Our results newly suggest that 1-MCP treatment can have different affects on tomato ethylene production depending on maturation stages (green or pink), but contribute to prolong the shelf life in both stages of tomato fruit.