tomato (lycopersicon esculentum mill.) fruits, cv. santa clara, were harvested at the breaker stage from commercial fields in brazlandia, brazil, to investigate the ability of 1-methylcyclopropene (1-mcp) to retard tomato fruit ripening. fruit without external blemishes were graded for size (diameter = 80±5 mm) and mass (m = 130±10 g), placed inside hermetically sealed boxes, and 1-mcp was applied for 12 hours (t = 22±1°c; rh = 80-85%) at four different concentrations: 0 (control), 250, 500 and 1000 ml.l-1. fruits were held at ambient conditions (t = 23±2°c; rh 80-85%) for 2 days and then stored inside a cold room (t = 20±1°c; rh = 85-95%). every 3 days, during a 15-day period, fruits were analyzed for firmness, total soluble solids, titratable acidity, external color, and total carotenoids. firmness of fruit treated with 1000 ml.l-1 was about 88% higher than control fruits after 17 days. the a*/b* ratio, an indicator of skin color, for fruit treated with 1000 ml.l-1 of 1-mcp was 38% lower than control fruits at the end of the storage period. treatments with higher concentrations of 1-mcp delayed total carotenoids synthesis and color development. control fruits stored for 17 days had about 190% more total carotenoids than fruits treated with 1000 ml.l-1 of 1-mcp. postharvest application of 1-mcp was an efficient method to delay tomato fruit ripening. as 1-mcp concentration increased, ripening was further delayed. tomatoes treated with 250, 500, and 1000 ml.l-1 of 1-mcp were delayed by 8 to 11, 11 to 13 and 15 to 17 days, respectively.