The objective of this study was to determine the effects of 1-MCP preharvest spray application on harvest synchrony, maturity, fruit quality, and marketable yield of cantaloupe. Seeds were planted in a commercial field on 16 Mar. (early planting, cv. Caravelle) and 4 Apr. (late planting, cv. Mission) 2005. Standard plant population, fertilization, irrigation, and pest control practices were followed. We evaluated three 1-MCP rates (5, 10, or 25 g·ha-1 a.i.) at three preharvest spraying times for the early (22, 15, and 7 days before harvest, DBH) or once for the late planting experiment (4 DBH). An additional test (late planting) compared fruit quality after storage for melons dipped with 1-MCP (0 or 10 mg·L-1). Fruits were harvested six times during June 2005 (early planting) and once on 19 July 2005 (late planting) and fruit quality parameters were measured at harvest and after storage. The preharvest 1-MCP application slightly delayed maturity and improved early harvest synchrony, but did not affect total marketable or yield by fruit size regardless of timing or rate of application. There was no effect of 1-MCP rate or application timing on fruit quality at harvest or after cold storage, except for an increased in fruit firmness (10%) in one of the six harvests. However, fruits treated with 1-MCP spray at 25 g·ha-1 a.i. (late planting) had higher firmness than those treated with lower rates after 9 days of storage. In addition, 1-MCP postharvest dipping significantly improved fruit firmness; however, a `greening' was evident in the fruit surface. Our results suggest that cantaloupe fruit quality was less affected by early preharvest spray application of 1-MCP applied at less than 25 g·ha-1 a.i. as compared to postharvest applications.