The effects of 1-methylcyclopropene (1-MCP) on quality parameters such as weight loss, firmness, color, titratable acidity, soluble solids, individual sugars and respiration rate of 'Black Diamond' plums during storage that were harvested at commercial ripening stage were determined. Plums were pre-cooled for six hours and treated with doses of 0.5 and 1 mu L L(-1) 1-MCP at the same date of harvest. Fruits maintained at the same conditions without any treatment were used as control. Fruits were stored for 30 days at 0 degrees C and 90% RH, and quality evaluations were performed at 15 and 30 days of storage plus five days of shelf life. Both 1-MCP doses were effective on reducing the weight loss and maintaining the firmness during storage and five days of shelf life. The other quality parameters, titratable acidity, color, total Soluble solids, individual sugars and respiration rate were similar to control fruits. According to the results, it can be concluded that both 1-MCP doses can be used to maintain the quality parameters of 'Black Diamond' plums harvested at commercial ripening stage during one month storage plus five days of shelf life.